Becoming a desperate Hypo

Hi there!
In Feb.09' I was sent to my O.B. to have some ovarian cysts looked at closer. I've been having problems in that area and my physician thought she should keep track of it since it is in her realm. Tests results came back and I had more than last time ( L side 1.5cm and rt side 3.5cm). She insisting on saying that it wasn't anything to worry about. O.k..... But she was concerned about my TSH level of 3.75, so then she decided to prescribe Levothyroxine.
During my first week on thyroid treatment without changing the the way I ate (healthy) in one week I put on 9.5 lbs.
Now I am one month into my medication and I've gained 13 lbs. My first visit with her she asked me many questions. "Was I gaining weight for no reason?" No, I wasn't I was at a very comfortable weight and now can't help but think that these meds. are the culprit. I have done many research and have come up blank. They basically state that it is medically impossible to receive weight gain during my Levothyroxine treatment.

I really need help. Is there anything (or a specific diet) I can do to help me shed some weight?

I keep my sodium in check, I don't add it to anything. I do not eat red meats and for the last year have been finding it hard to eat any meat at all. I don't drink soda or eat Sugar unless it comes from fruits. I don't eat excessive fruits either. I'm seriously lost.

Please help me.