thyroid cancer?

I was diagnosed with pappillary thyroid cancer with a follicular varient in November 2006. They removed 1/2 of the thyroid for the biopsy then the remainder after they determined it was cancer. They then did I-131 my doctor is wanting me to become hyperthyroid. He want’s my TSH .003, They have increased my Synthroid steadily over the last few months. I am now on 150 mcg. I am now starting to gain weight and am extremely tired. I called my doctor today and he told me there isn’t anything he can do until I have been on the synthyroid for 4 weeks. He said this could be due to another condition, that I would need to contact my pcp for this. I think this has to do with my thyroid. Has anyone had this happen? I gained about 10lbs in the last 2 weeks.