Hi there! I am so sorry to hear about this. I know that antidepressants can really affect your weight. I took some in the past that made me gain weight, luckily not a lot, but I had to literally drink only protein shakes and eat fruits and veggies to NOT gain weight. As soon as I went off them, I lost weight very easily with diet and exercise. It definitely makes it very difficult! In my experience, I was NOT happy while taking the medication and felt insecure about gaining weight since I had body image problems, so I decided I'd be better off without them. Exercising was what helped me become happier and more relaxed, plus I lost the extra pounds I gained.
Definitely talk to your doctor about this. Perhaps they can take a look at your medication and see if there is anything else they can tweak. I recently went on Prozac (after a while of being scared to go on antidepressants, but this time it's more for anxiety). Prozac seemed to have a smaller risk of weight gain, and so far, no weight gain at all! In fact, I feel like I've been eating more, yet I work out a lot, so could just be from that. I explained to my doctor that weight gain would make me not want to take the medicine at all, so she helped me find my best option. My old antidepressant wasn't all that affective anyway.. just made me sleepy, and thus, I guess I wasn't getting upset as often because all I felt was tiredness (not the way I hoped to feel)!
I'm not sure if changing medications (or dosage) is an option for you, but don't be afraid to talk to your doctor about it. I felt that I had to specifically explain to mine what I did want and what I didn't want. Being happy overall is most important to me, and I decided that being healthy and in shape is just part of that. I feel more confident and comfortable when I can stay at a healthy weight, and I think everyone deserves to feel happy with themselves! I hope things work out better for you and hope you can find something that works out well