Your initial reports of thyroid profile were suggestive of thyrotoxicosis not necessarily hyperthyroidism. Thyrotoxicosis is a broad term and means signs and symptoms due to high circulating thyroid hormones. Hyperthyroidism means that thyrotoxicosis is due to hyper function of thyroid gland and this can be easily demonstrated by doing thyroid uptake studies. Other cause of thyrotoxicosis is thyroiditis and your profile can be easily due to thyroiditis. I suggest you to stop the neomercazole for the time being and repeat your TSH and fT4 after two weeks and four weeks. Once TSH is low get a thyroid uptake study done and if uptake is high then you have hyperthyroidism otherwise thyroiditis. Treatment for hyperthyroidism is either medications like neomercazole or radioablation or surgery (if gland is very big). If uptake is low then you are likely to have thyroiditis for treatment is symptomatic and observation. In case your TSH remains high even after four weeks then you have hypothyroidism and will need thyroxine as treatment. Anti-TPO is a good test to differentiate between these two conditions.