s Thyroiditis, which is an autoimmune disease that attacks the thyroid. If you have symptoms of hyperthyroidism, such as
weight loss, rapid heart rate, palpitations, etc you should also get Thyroid Stimulating Immunoglobulins (TSI) to confirm/rule out Graves Disease, which is another autoimmune disease that attacks the thyroid.
You should also get vitamin B12 tested, as B12 deficiency can cause horrendous fatigue, as well as tingling/numbness in the hands/feet, easy bruising, etc.