Sounds like a potential toxic thyroid condition. Do not assume thyroid blood tests are accurate, see an endocrinologist. My family doctor about killed me relying on routine blood work.
even most endos are completely clueless about the thyroid. they depend almost solely on TSH which is a pituitary hormone, not thyroid. And that doesn’t tell the whole story, at all. They also prescribe T4 only which is unhelpful and never encourage thyroid supporting supps which are iodine, selenium, mag, vit c and salt