I understand just how you feel as I have gained on Cymbalta and yet my pdoc argues with me that it is not known for weight gain............. Some people lose on the AD meds when they first start them but most end up gaining weight.
I know Remeron is usually saved as it works well by the side effect of weight gain is not healthy either. I agree to discuss the problem with your physician.
Also try to exercise, which I know can be boring and sometimes feels like just one more thing we need to do but it truly may help you hold the weight down.