hello
i had gone through your question and i can understand your concern
you are right, antidepressant causes weight gain by various mechanism
you can reduce your weight by following these guidelines
strictly follow your schedule of exercise and diet control
don't skip the meal
small and frequent feeding 3 meals and 3 snacks in between
avoid carbonated drinks fatty and junk food
have well cooked home made food more of boiled vegetables and salads
have plenty of fluids lukewarm water and fresh juices 2 to 3 liters a day
Have dietary fibers in diet to keep the 
colon healthy
i hope you find my response will be informative and helpful please feel free to ask for further clarifications i will be happy to help you
wishing you a very good health
Regards