TSH is a pituitary hormone that is affected by so many things that at best it is just an indicator to be considered along with more important indicators such as symptoms and the biologically active thyroid hormones Free T4 and Free T3. You have multiple symptoms of hypothyroidism. The doctor said nothing is wrong because obviously he has the "Immaculate TSH Belief", which just doesn't work for many people.. After you were tested for FT4 and FT3, the doctor used "Reference Range Endocrinology", by which any test result that falls anywhere within range is supposedly adequate. That also is wrong because of the erroneous assumptions used to establish the ranges'
In the words of a good thyroid doctor, "The free T3 is not as helpful in untreated persons as the free T4 because in the light of a rather low FT4 the body will convert more T4 to T3 to maintain thyroid effect as well as is possible. So the person with a rather low FT4 and high-in-range FT3 may still be hypothyroid. However, if the FT4 is below 1.3 and the FT3 is also rather low, say below 3.4 (range 2 to 4.4 at LabCorp) then its likely that hypothyroidism is the cause of a person's symptoms."
You obviously are hypothyroid based on symptoms and low in the range FT4 and FT3. Based on your relatively low TSH along with those FT4 and Ft3 results you appear to have central hypothyroidism. Central is a dysfunction in the hypothalamus/pituitary system that results in TSH level that are too low to adequately stimulate the thyroid gland. You are going to have to get your doctor to reconsider and treat you or find a good thyroid doctor that will do so. Note that good thyroid doctor does not automatically mean an Endo.
One thing further is that hypo patients are frequently too low in the ranges for Vitamin D, B12 and ferritin. So you should make sure to test for those and supplement as needed to optimize. D should be about 55, B12 in the very upper end of its rane, and ferritin should be about 70.
Before further discussion please post the reference ranges shown on the lab report for those tests.
The prevailing belief is that hypothyroidism is "inadequate thyroid hormone", correctly sensed by the pituitary, which then secretes TSH to stimulate the thyroid gland to produce more thyroid hormone. So most doctors are taught that TSH is all that they need to diagnose and treat a hypothyroid patient. That is demonstrably wrong, so TSH fails as a primary diagnostic, except at extreme levels. First because TSH has only a weak correlation with the actual biologically active thyroid hormones Free T4 and Free T3, and has a negligible correlation with symptoms, which are the patients' concern. Even when testing is expanded, Free T4 has only a weak correlation with symptoms.
So the best place to start is with an understanding that the correct definition for hypothyroidism is: "Insufficient T3 effect in tissue throughout the body due to inadequate levels of, or response to, thyroid hormone". This definition recognizes that both thyroid hormone levels and cellular response determine the person's thyroid status. So hypothyroidism and associated symptoms result from insufficient Tissue T3 Effect. There is no direct test for Tissue T3 Effect, so we are left with using indirect measures instead. Of those the most important is an evaluation for symptoms that occur more frequently with hypothyroidism than otherwise. Along with that testing should be expanded to include not only Free T4 and Free T3, but arguably Reverse T3, cortisol, Vitamin D, B12 and ferritin. Except at extreme levels, TSH is useful only to distinguish primary from central hypothyroidism.
You said that your symptoms were similar to the prior member, so we'll assume that you have many that are typical of hypothyroidism. The problem will be to get your doctor to recognize your many symptoms as well as interpret your test results correctly. Looking at your Free T4 of 1.0 it is only at 20% of its range. Your Free T3 of 2.6 is only about 16% of its range. To assess those further, have a look at this statement from an excellent thyroid doctor, "The free T3 is not as helpful in untreated persons as the free T4 because in the light of a rather low FT4 the body will convert more T4 to T3 to maintain thyroid effect as well as is possible. So the person with a rather low FT4 and high-in-range FT3 may still be hypothyroid. However, if the FT4 is below 1.3 and the FT3 is also rather low, say below 3.4 (range 2 to 4.4 at LabCorp) then its likely that hypothyroidism is the cause of a person's symptoms." Along with your symptoms, having both your FT4 and FT3 in the lower part of their ranges are strong evidence for hypothyroidism.
So from the symptoms and your FT4/FT3/TSH test results the cause appears to be central hypothyroidism. With central there is a disorder in the hypothalamus/pituitary system resulting in insufficient output of TSH to adequately stimulate the thyroid gland to produce hormone. That in itself indicates the need for a complete evaluation and biochemical testing of the pituitary hormones and dependent organs. One of the hormones that may be affected is cortisol, so that also should be tested, since it affects thyroid metabolism.
You haven't mentioned your doctor's response those test results. Typically symptoms are ignored and you would be told that everything is "normal" and nothing further is needed. Obviously that is very wrong. You need to be started on a dose of thyroid med, and then increased until the FT/FT3 levels are raised into the upper half of their ranges. If symptoms ease, then this is confirmation of hypothyroidism and levels should be increased as needed to eliminate the signs/symptoms of hypothyroidism without creating any signs/symptoms of hyperthyroidism. A recent, excellent scientific paper concluded that: "Hypothyroid symptom relief was associated with both a T4 dose giving TSH-suppression below the lower reference limit and FT3 elevated further into the upper half of its reference range." Note that patients starting on T4 med often find that their body does not adequately convert the T4 to T3, so they have to add a source of T3 to their med. If you convince your doctor to medicate you, and you have any say in what mediation, I suggest asking for a desiccated, natural thyroid like NatureThroid, or Armour Thyroid.
In addition to getting adequate thyroid med there are other variables that affect the response to thyroid hormone and they need to be tested and confirmed as optimal, or supplemented as needed. So you need to test for cortisol. Also Vitamin D, B12 and ferritin need to be tested and optimized. D should be at least 50 ng/mL, B12 in the upper part of its range, and ferritin should be at least 100.
If you want to confirm what I have said, please click on my name and then scroll down and read at least the one page overview of a full paper on Diagnosis and Treatment of Hypothyroidism: A Patient';s Perspective.
So I would start with your doctor by making a copy of the following link and circle the symptoms you have and give that to your doctor. Also give him a copy of the one page overview, and relate that you would like to be diagnosed and treated clinically, rather than just based on TSH/FT4 compared to reference ranges. IF the doctor resists doing the additional tests and clinical diagnosis and treatment, then you will have to find a good thyroid doctor that will do so.
I don't see it as Wilson's. Wilson's is commonly called Reverse T3 dominance. I doubt you were even tested for RT3. Also don't know what would be learned by an ultrasound. Based on all those symptoms and your Free T4 and Free T3 levels it appears to be central hypothyroidism. So starting on thyroid med is the right direction and the 75mcg is an adequate starting dose. Please note that serum thyroid levels are the sum of both natural thyroid and thyroid med. So when when taking thyroid med the TSH will drop and the output of natural thyroid hormone is reduced resulting in little or no change. Only when the dosage is enough to essentially suppress TSH, will further dosage increases start to raise your FT4 and FT3 levels.
When your TSH becomes suppressed, don't let your doctor tell you that you are hyperthyroid and need to reduce your med dosage. You are hyper only when having hyper symptoms due to excessive levels of FT4 and FT3. With central hypothyroidism patients typically will have suppressed TSH when taking adequate thyroid med. Also note this conclusion from a recent, excellent scientific study Hypothyroid symptom relief was associated with both a T4 dose giving TSH-suppression below the lower reference limit and FT3 elevated further into the upper half of its reference range." Symptom relief should be all important, not just test results.
In addition, hypothyroid patients are frequently deficient in other very important areas. So you should make sure they test for cortisol to assure it is okay. Also, you should be tested for Vitamin D, B12 and ferritin and then supplement as needed to optimize. D should be at least 50 ng/mL, B12 in the upper end of its range, and ferritin should be at least 100. As you said, low B12 may also be a contributor to the high MCH test result.
The short answer is yes. Note this info from the American Thyroid Assn.
"We do not know what causes most thyroid nodules but they are extremely common. By age 60, about one-half of all people have a thyroid nodule that can be found either through examination or with imaging. Fortunately, over 90% of such nodules are benign. Hashimoto’s thyroiditis, which is the most common cause of hypothyroidism (see Hypothyroidism brochure), is associated with an increased risk of thyroid nodules. Iodine deficiency, which is very uncommon in the United States, is also known to cause thyroid nodules."
From your statement about your symptoms and your test results, being treated for hypothyroidism is the correct. Do make sure to get the other tests and then supplement as needed to optimize.