I believe your instinct to take selenomethionine is correct. It protects your thyroid from "too much" iodine, which could include the doses you took that were more than you'd taken before. I don't know if this will restore your feeling of well-being, but it's logical to do. Also Vit C 2-4 grams and a B complex. Oh, and magnesium citrate or malate, 400-600 mg. Hopefully you get enough protein to support your athletic lifestyle, as well as enough zinc and iron in your diet. Iron is surprisingly important in thyroid function. Good luck!
Laboratory for Human Nutrition, Swiss Federal Institute of Technology, Zürich, Switzerland. Michael.email@example.com
Several minerals and trace elements are essential for normal thyroid hormone metabolism, e.g., iodine, iron, selenium, and zinc. Coexisting deficiencies of these elements can impair thyroid function. Iron deficiency impairs thyroid hormone synthesis by reducing activity of heme-dependent thyroid peroxidase. Iron-deficiency anemia blunts and iron supplementation improves the efficacy of iodine supplementation. Combined selenium and iodine deficiency leads to myxedematous cretinism. The normal thyroid gland retains high selenium concentrations even under conditions of inadequate selenium supply and expresses many of the known selenocysteine-containing proteins. Among these selenoproteins are the glutathione peroxidase, deiodinase, and thioredoxine reductase families of enzymes. Adequate selenium nutrition supports efficient thyroid hormone synthesis and metabolism and protects the thyroid gland from damage by excessive iodide exposure. In regions of combined severe iodine and selenium deficiency, normalization of iodine supply is mandatory before initiation of selenium supplementation in order to prevent hypothyroidism. Selenium deficiency and disturbed thyroid hormone economy may develop under conditions of special dietary regimens such as long-term total parenteral nutrition, phenylketonuria diet, cystic fibrosis, or may be the result of imbalanced nutrition in children, elderly people, or sick patients.