There was a big show On CBC TV on depression and Zoloft, Paxil, and Prozac. I am not sure of the spelling.
Anyway, they were saying that these meds have to be weaned out of your system slowly and that you should no be doing it on your own. Sound like you are crashing and you need help.This could be dangerous for you .
I am on Effexor XR, which does not promote weight gain.
Hope this help you, go see your doctor for help.
Pene