You need to start taking Iodine, Lugol’s 5% solution. Thyroxine and other drugs don’t help the thyroid they mask symptoms. To check if you need Iodine, do a Basal temperature test, google it to find out the method. Another thing you want to check if your adrenals are healthy and not fatigued. Check out videos on YouTube about AF.
I would not take any drugs or supplements during a water fast. If you have AF, please don’t fast.