Welcome to the forum. It sure sounds like you might have Hashimoto's which can cause a
person to alternate from hypothyroidism to hyperthyroidism. You mention that you have had
antibody tests. Did you have both Thyroid peroxidase antibody (TPO Ab) and thyroglobulin
antibody ( Tg Ab) tests? Make sure that you have both tests done and if they did come
back in the normal range, I would get retested when your symptoms are present. The
tests can fluctuate so just because they are normal at one time, they can change when
your thyroid gland is getting attacked.