You should ask your doctor to order thyroid antibody tests to determine if you have Hashimoto's Thyroiditis, which is an autoimmune thyroid disease. With Hashimoto's, your body sees your thyroid as foreign and produces antibodies to destroy it. As the destruction progresses, your thyroid produces less and less hormones.
The antibody tests you need are Thyroid Peroxidase Antibodies (TPOab) and Thyroglobulin Antibodies (TgAb). You need them both, since they are both markers for Hashimoto's.
Typically, as thyroid hormone levels go down, TSH goes up; yours is not, at this point, which me wonder if something else is causing your problem. Either way, you will need thyroid hormone replacement.
Many people have found tha tbing "in range" means nothing about feeling well. The ranges are established mathmatically and have NOTHING to do with optimum levels. It simply means that 95% of the people being tested fall within those limits.
Mathmatically if 100% of the people are sick, and you tested them, they woudl come out with a range showing that 95% of them are "normal". But in reality not a single one of them is well.
So ask yourself who is likely to get tested for thyroid hormones in the first place? Answer: People who are at least of the belief that they may have a thyroid condition. So right off the start the population of data for the base is established on SUSPECTED people who are sick. In other words nearly 100% of the people getting tested are possibly sick. So when they test these potential 100% they get results and then "determmine" that 95% of them are "normal". And that ONLY the very sickest 2.5% at the bottom are Hypo and those sickest 2.5% at the top are Hyper and everybody else is "just fine".
You can see how absurd this is!
As a result many people here have found that the rule of thumb target to shoot for in order to become symptom free is to have BOTH of the following:
1) Free T4 (FT4) to be in the MIDDLE of the range (50%) or a bit higher
AND- that means in addition
2) Free T3 (FT3) to be at least 50% to the UPPER 1/3 of the range (66.7%).
Your test results are
FT4 is only 12% of the range which is a FAR cry from 50%
Your FT3 is ZERO percent (0%) of the range which is again a far cry from 50% to 67%.
Both of these could cleary suggest that you are likely Hypo and are symptomatic.
And think about this. If you see a bird, and the bird has feathers, and the bird quacks, Most reasonable thinking person would come to the conclusion that the bird is a Duck. You are symptomatic consistent with being Hypo so you are a bird with feathers, your tests are very low in the ranges, and would be the equivilent of a quack. And your Dr comes to the conclusion that you are not even a bird, let alone a duck. Hummmmm.
TSH test is a screening test at best and nearly completely worthless for true determination of thyroid health, especially in someone who is symptomatic consistent with low thyroid. Unfortunately Dr's are taught in medical school that TSH is the gold standard and accurately predicts a person's thyroid condition. This is complete male bovine manure!
Dr's are taught that a TSH between 1.0 and 2.0 is "perfect" and as long as that is true, the patient is fine and some other ailment or mental issue is at hand and to rule out thyroid. As I said this is one of the biggest medical tragedy's in the industry in my opinion. Many if not most people end up on this site or other online thyroid groups out of desparation due to this scourge of the medical industry. And many end up suffering needlessly or taking antidepressants or other drugs to cover up or try to fix the symptoms and never get to the root cause of their inadequate thyroid condition.
You need to become your own best advocate. Do not simply rely on the so called "experts" and suffer. Educate yourself and continue to look for and find a Dr who will treat you.
I expect the doctor was referring to your relatively low in the range TSH, which is all that many doctors use to diagnose and treat thyroid patients. Unfortunately that is wrong and doesn't work. In your case, having symptoms typical of hypothyroidism but a low TSH only indicates the possibility of central hypothyroidism, which is a malfunction in the hypothalamus/pituitary area resulting in insufficient TSH to stimulate thyroid gland production of thyroid hormone. Your Free T4 and Free T3 are at the very low end of the ranges, so I expect that you are having significant hypo symptoms.
A good thyroid doctor will treat a hypo patient clinically by testing and adjusting Free T3 and Free T4 as necessary to relieve symptoms, without being constrained by resultant TSH levels. You can get some good insight into clinical treatment from this letter written by a good thyroid doctor for patients that he sometimes consults with after initial tests and evaluation. The letter is then sent to the participating doctor of the patient to help guide treatment. In the letter, please note the statement, "the ultimate
criterion for dose adjustment must always be the clinical response of the patient."
http://hormonerestoration.com/files/ThyroidPMD.pdf
So you most need a good thyroid doctor, which doesn't necessarily mean an Endo. If you will tell us your location perhaps we can recommend a good thyroid doctor in your area.