I have been on the same roller coaster (Not as long as you though) and now after 2.5 years they realized I do not convert T4 (Synthroid) to T3, so even though my T4 came out fine, my T3 was to low and is causing my symptoms, why no one could catch this before, I don't know. Now I have to decide wether to take Armour (Has both 3&4) or take a supplement with the Synthroid, I just posted that question for opinions but no response yet. So just post when you get it together, I will sign it, because it is rare to find regular MD's that will prescribe Armour. Good Luck FTB4
From your description, I'd bet a good cup of coffee that your doctor is one of those with the "Immaculate TSH Belief" that incorrectly thinks that TSH is all that is needed to diagnose and medicate a thyroid patient. Wrong!!!!! TSH is a pituitary hormone that is affected by so many variables that at best it is only an indicator, to be considered along with more important indicators such as symptoms, and also the levels of the biologically active thyroid hormones, free T3 and free T4. Note that I said FT3 and FT4, not total T3 and total T4.
A good thyroid doctor will treat a patient clinically by testing and adjusting FT3 and FT4 as necessary to relieve symptoms, without being constrained by resultant TSH levels. Symptom relief should be all important, not test results. If your current doctor is unwilling to treat you in this manner, then you are going to have to pressure him to change, or else find a good thyroid doctor.
If you have any doubts that being treated clinically as I describe is the right approach, then read this link. It is a letter from a very good thyroid doctor. for patients that he consults with that live some distance away, the letter is sent to the PCP of the patient, to help guide treatment.
http://hormonerestoration.com/files/ThyroidPMD.pdf