Your Dr has you on a roller coaster ride of hell. All because the Dr is using TSH which is TOTALLY inadequate to adjust dosage on. Secondly you say the Dr originally put you on a large dosage of T4 medication. How large? If it was in excess of about 50 mcg then that was NOT the way to do it.
All of these things suggest that your Dr is not familiar with the best ways to treat hypo and you should really either educate your Dr (after you get educated yourself) or you should find another Dr.
The typical way to treat Thyroid so it doesn't "shock" the body is to start introducing thyroid medication in small doses and work your way up in dosages after testing and checking with symptom relief.
It is not uncommon for someone who starts meds to feel WORSE initially. THis is because your body is not used to having thyroid hormone and has made its best job to make up for that. When you add in the medication now the body has to readjust itself. This is why it is best to start out low and slowly work up dosages. What Your Dr did was give you a huge starting dosage so you slammed the body, it tried to adjust, the TSH dropped in the shock response. Then as the TSH test your Dr saw the shock result and then sent another shock wave to the body by lowering your dosage. As long as the Dr uses TSH and clearly unfamiliar with how to properly treat and dose thyroid, you will be kept on the roller coaster ride and most likely be kept feeling terrible.
TSH is a screening test at best. After that, TSH in my opinion is almost irrelevant. What becomes important is the Free T4 and Free T3 tests along and maybe most importantly with your symptoms. Again dosages are set in small increments and then reevaluation of how you feel, if the last dosage change made you feel better or worse and look at the lab results to see how much of an impact the dosage change had. With correlating the blood labs to how you feel, you can slowly work to reach optimum level.
That is the best theory at least. In life nothing is usually that simple. As if you have Hashhimotoes and decreased thyroid or variable thyroid gland production etc is going on in the background makes it a bit more complex. But the idea remains the same.
Understand that your body ONLY uses the Free T4 and ultimately at the cellular level the ONLY thing that is used is the Free T3 hormone. This is why it is so important if not critical that these tests be completed.
Also understand that Total T4 and Total T3 are different and outdated and less valuable tests. So you must DEMAND nand be SPECIFIC about asking for the "Free T4", and "Free T3" tests.
the "free" designation has nothing to do with cost. Rather it is signifying that the thyroid hormone is all by itself. Much of the hormone becomes attached to a protein. Once attached it becomes biologically inert. So Total measures BOTH the free and attached hormone. While th "free" test only counts or measures the amount of hormone that is isolated and "free" from being attached to the protein. Your body ONLY uses the "Free" and isolated hormone. Again this is why it is so critical to get measured.
First, doctors do not understand or accept the scientific evidence that hypo patients taking adequate doses of thyroid med often find that their TSH becomes suppressed. That does not mean that you have become hyper, unless you have hyper symptoms, due to excessive levels of Free T3 and Free T4, which you do not have. So dosing a patient based on TSH is just wrong and does not achieve the goal of relieving symptoms and maintaining some stability for the patient.
Second, just because your Free T4 and Free T3 are within the ranges does not mean that all is well for you. Due to the erroneous procedures for establishing ranges, they are far too broad to be functional across their entire breadth for every hypo patient. Ranges that were correctly established based on test results from healthy adults with no known thyroid pathology would look more like the upper half of the current ranges. As a result many of our members say that hypo symptom relief required Free T3 in the upper part of its range and Free T4 at the middle of its range, at minimum.
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 from this link written by a good thyroid doctor.
http://www.hormonerestoration.com/Thyroid.html
So, I recommend a good discussion with your doctor to find out if he is willing to treat clinically, as described. If not, then you need to find a good thyroid doctor that will do so. In addition, if not tested for Vitamin D, B12 and ferritin, those should be done also since hypo patients are frequently too low in the range for those as well.
Try taking medication at night. Also look at lifestyle factors to help as well. My tips include decreasing stress (I find exercise in particular helps with stress), increasing antioxidants which include A, C, E and selenium, quit smoking and drinking (if you are doing so), drink good quality water, decrease added sugar and processed carbs in your diet. I'm very stable with my thyroid issues unless I'm under immense stress and this causes hyperthyroid symptoms for me.