thanks for asking few questions *When was first noticed? *Has it increased in size since then? Any recent increase in size? *Do you have any breathing difficulty/ swallowing difficulty or any voice change? *Any history of weight loss/palpitations/ tremors/diarrhea? *Any associated weight gain/ hairloss/ tiredness/ constipation? *Any history of recurrent fever / thyroid pain/ eye pain / bulging eye ball/ tiredness? *Periods- is it regular? *How is your quality of life? *Any family history of thyroid disease/ goiter or thyroid malignancy? *Are you diabetic/ hypertensive? *Do you have raised cholesterol? if your TSH was normal when you were taking 75mcg then you should probably take 75 I to think you might be over dosed do a TSH/ Free T4