I agree with Gimel. Time to go Dr shopping!
Your current Dr has proved to keep yo ufeeling horrible for maybe 5 YEARS!
Time to become your own best advocate. That means two broad things.
1) Educate yourself. Read a TON here and other sources. You are literelly going in to battle for your health. Go into that battle as well armed as you can be. That means gaining knowledge. There is a TON of knowledge here so read and ask questions etc. If you spend much time reading here you will find that it is common to find that the general medical industry today is NOT at all informed about how to properly treat thyroid. And it is extremely common for people to have to switch Dr's sometimes several times in order to find one who will actually treat you until you feel well!
2) Start the search of a New Dr. The Dr does NOT need to be an endo. As you have already proven, Endo's are not the end all be all. They often times now only concentrate on Diabetes and many know little more than a GP Dr. Many have also found that too many Endo's have huge ego's and they can tend to get extremely defensive when challenged. they simply expect that they are the expert and you have no right to question them. While this is true for many Dr's in general, it seems even higher level when dealing with a so called "expert" of the Endo.
Understand that you are a human being, and so are the Dr's. Sure they have studied a lot to get their medical degree. But that doesn't mean that they are some sort of super human and they have some special gift of learning and educating that you do not possess. Besides, you have time to study only a single issue (thyroid) while Dr's have to know a little bit about a 1,000 different things. So it is reasonable to expect that you can actually obtain MORE knowledge than a degreed person simply because of immersion in a single topic over time.
Bottom line, Do NOT let Dr's bully you! YOu know how you feel, and armed with proper and correct information, you owe it to yourself to pursue whatever means you can muster in order to get treated in order to feel well.
As for some assurance. My wife used to have migrains. and acid reflux. And once she got more thyroid medication, her acid reflux went away and then her migrains went away (for the most part).
So getting properly treated and replacement hormones optimized and you feeling well can affect the quality of your life.
Unfortunately your title of the thread is where people HAVE to get to in order to finally get the necessary motivation to get proper treatement.
Unfortunately your doctor seems to have the "Immaculate TSH Belief" by which he thinks that a TSH result that falls in the range is all he really needs to know. That is very wrong. Perhaps he has forgotten about the possibility of central hypothyroidism. With central hypothyroidism, there is a dysfunction in the hypothalamus/pituitary system resulting in levels of TSH that are inadequate to stimulate the thyroid gland. The result is relatively low TSH, along with Free T4 and Free T3 that are too low in the range and result in hypo symptoms.
Since the doctor is ignoring your hypo symptoms and hasn't even tested for your Free T3 level tells me that most likely the best thing to say to him is "goodbye", and find a good thyroid doctor. By that I mean one that will treat clinically by testing and adjusting FT4 and FT3 as needed to relieve symptoms, without being constrained by resultant TSH levels. Symptom relief should be all important, not just test results, and especially not just TSH. Many of us have found that symptom relief required FT4 at the middle of its range, at minimum, and FT3 in the upper end of its range, adjusted as needed to relieve symptoms.
In addition, hypo patients are frequently too low in the ranges for Vitamin D, B12 and ferritin. D should be about 55, B12 in the upper end of its range, and ferritin should be about 70. You should get those tested and supplement as needed to optimize.
If you will tell us your location perhaps we can give you names of doctors in your area that have been recommended by other hypo patients.