I definitely understand the weight gain due to the meds. I'm sure it's somewhat common.

I don't at all want to suggest any change to meds - however, I just read about Depakote and the side effects seen with it. With what I found using Google, it looks like weight gain is part of the side effects. One person said they gained 70 lbs on it. Later, they switched meds and lost 60 lbs from there. I won't post the actual URLs but did find it with a Google search of "effects of depakote weight gain".

Good luck - you've probably done the research so I'm preaching to the choir.