Chub symptoms and conditions

I have just been put on Neurontin and found out about this weight gain thing!! I am freaked out. I have come off of Topamax due to I could not handle the side effects and I was like I was in a coma. I am also on lexapro for depression so the topamax really effected me. The Neurontin has said to be given to bi polar patients but from what I have read people are having depression problems on it. So the whole weight gain and the depression thing is scaring me.