I agree with the others: Get copies of your labs (I track mine on a spreadsheet) and find a new doctor. And don’t give up! It took me a year to find my correct dose of methimazole, but then I did well on it for three years. It took me so long because I actually started at 20 mg and worked my way up to 60, then became very hypo. I had to taper down and then go off of it for a while. When I became hyper again, I started over again at a much lower dose (10 mg) and eventually settled at alternating 5 and 10 mg (breaking the tablets in half). I never had my antibodies tested, but my best guess is that they’re the reason for my sudden switch to hypo.
Unless you develop an allergy or side effects or something, you should eventually find your way to your correct dose. Good luck!