Why can't I gain weight? I'm losing weight. I have a good appetite. I'm only taking 1/2 of Methimazole from a 5 mg pill once a day. Told Therapist and she said I look good...where's my weight I'm supposed to gain going? I've been diagnosed with Hashimoto and Graves Disease. Therapist said my Thyroid is fine, since she's felt nothing there at all to be concern. Off and on on breathing problems since I feel I can't breathe deeply. Thank You so much for comments.