You mentioned fasting, the only thing I can say is, I used to be able to fast, ... the first day I fasted about 8 months ago, gobs of my hair started to fall out and that's when I realized something was wrong with my thyroid. I had never experienced anything like it. I did tons of research and realized people with thyroid issues should not fast. and until I get my body back on track, I will not fast. I know my body needs the nutrients to heal.
But you have to do what's right for you and listen to your body.