Many of these meds cause weight gain. Your choice is whether that's worse than how you were feeling, assuming you eliminated all other forms of treatment before trying medication. As this med is very hard to stop taking, don't stop abruptly (don't stop any of these abruptly), taper off as slowly as you need to if you decide you don't want to continue on this medication. Try buying a book called The AntiDepressant Survival Guide and see if it gives you some thoughts on how to change your lifestyle to not gain as much weight if you decide to stay on the med.