I had great success with Prozac, and no weight gain. We all respond differently to these types of drugs, and what one experiences with a drug, another may not. I'm assuming your doctor felt the Prozac would be better for you weight wise or he would not have changed your medication. You won't know until you take it, but it's been around a long time, and many have had great results. Good luck and take care.
Yes unfortunately antidepressants are often related to weight gain. Sounds like you got it right with Prozac because Prozac and Zoloft are two antidepressant that are supposed to have the less impact on your weight.
M4