Greetings ! Welcome to the site. Well both from your symptoms and your Thyroid function test which shows low levels of TSH, it appears like you are suffering from what is called as Hyperthyroidism which is a condition where the thyroid hormone is being produced at higher levels than it is required thereby leading to increased levels in the blood. Since TSH is a regulating hormone of T3, T4 thyroid hormones, so it s low levels in the blood indicate poor regulation of these hormones and hence development of Hyperthyroidism owing to increased thyroid hormone levels. However having said that this condition is treatable so I suggest that you consult an endocrinologist and discuss with him your blood test results as well as use of drugs like propylthiouracil and methimazole for your underlying condition as they are used for treating this condition effectively. I hope this helps. Wish you all the best. Regards.