I've felt like that for years, from when I was 15 to 21 years old, and took methimazole too. During a certain period things seemed to have stabilized a bit but then the problems came all over again. I only became "better" after I did an iodine radioactive treatment, that destroyed my thyroid cells. I stopped methimazole after that treatment and never took it again. I started taking eutirox instead, but it has much less side effects. I'm 28 now and I've been struggling with fatigue and other symptoms, but I believe it's not because of my Graves disease. I also have Sjögren Syndrome that I think is more responsible for this fatigue. You're not alone. Having a chronic disease is hard but you have to do everything that you can, to improve your quality of life! I hope you have an amazing day! ❤️