Marginalia --
I hope you will either find a new doctor or go back to the old one and have the thyroid tested again. There are at least two different ways to test the thyroid. Our more scientifically astute members of the fora can provide the details. In humanities terms, one test measures output and the other measures something different, like ability to use or something. You need both tests. With the initial test, your thyroid function can show up as normal when it really isn't.
And I second the suggestion that you be tested for diabetes.
I would add, on the thyroid issue, that if your doctor is not an endocrinologist or not on top of changes in thyroid testing, there's a "new normal" that's much, much lower than some labs and doctors use. I had a general practitioner tell me my thyroid was normal, and I knew something was wrong. I went to an endo who found that my thyroid was nowhere near normal, put me on a low dose of synthroid, and it worked wonders. Good luck!