Your problem seems to be related to be your blood (serum) Calcium levels as a result of your surgery. It would have been helpful to know the immediate post operative calcium levels, were you treated with intravenous calcium supplementation in the post operative period and what has been the serum calcium level along with your thyroid profile on different occasions during these 6 months after your surgery; to be able to really comment on your problem. Your treating endocrinologist would be in a better position to comment on this.