I've heard of too many people, usually women, who face pretty much exactly what you present here. You are on a dose of thyroid replacement hormone that should provide you with normal zip and vigour, yet your body is telling you it is starving for thyroid hormone.

The solution is not to cut the dose of T4, as your doctor is doing. Some people do not convert T4 effectively into the more active T3. What I have heard consistently is that Armour thyroid (standardized dessicated pig thyroid), or a combination of T3 (e.g. Cytomel) and T4 (e.g Synthroid or Levoxyl), solves the problem. Some tissues just have to have T3, or so it would seem.

It may mean you need to find another doctor. I don't know, doctors are pretty stubborn about this. Some understand, and some don't.

Best of luck,
Lar