Large amounts of weight gain

Well, to start, I've had health problems and wight problems all my life. In high school, I was able to drop, but it never stayed that way. By the time I was 17, my weight was steady around 160. Last year I was diagnosed with Lupus, and since then was put on countless medications and tests. I've had endoscopes, coronary catheterization, many hospital stays... you name it. Then, a couple months ago, another doctor told me it was a false diagnosis, I only had fibromyalgia and an auto-immune thyroid(making me hypothyroid). However, I also noticed I have tipped the scale to 200lbs. This was a shock, I've never been this heavy in my life. Since then, I've been riding my bike around town for an hour every day... now I'm 225lbs.
I was hoping that the weight gain was due to the meds I was on for Lupus, but I've been off of them for so long now and am still gaining weight... dieting and exercise are not working... I'm really at a loss of what to do. I hate looking at myself in the mirror and noticing my back has boobs.

I know I'm not pregnant, not only have my periods been regular, I'm on birth control, and it's been too much of a gain to be pregnancy.
I'm only 20, I shouldn't be having all of these issues, and it shouldn't be this hard to lose weight... I'd be happy to be 160 again.

[BrownT]

Hello, thanks a lot for sharing this post. :D It serves as an inspiration for me to lose my excess weight. Cheers! :D