MsSunflower, you are not alone. While stopping the meds was the only thing that worked for me, and even still the weight was very difficult to lose. Depression and sleep deprivation has me carrying the almost the same amount once again, years later. Now as of last week out of desperation I'm back on the same med that made me gain so much weight years ago. I'm floundering my way through it, and I have no advice at this point.

We are very much not alone, there a several threads on this topic, here are two of the most recent ones, they might offer some insight, or at least commiseration.

Physical Check-In

How does a bipolar person stay fit and thin?