Hello! I've been on a couple of different anti-depressants over the years; Prozac and Lexapro. I gained about 40 lbs which is a lot. My doctor prescribed me Wellbutrin SR 150mg twice a day. However, she told me to stay on Lexapro for awhile. The other anti-depressants made me hungry all the time and I'm a bit of an overeater. This is my 2nd day on Wellbutrin. My question is: How long does it take for me to feel the effect of Wellbutrin? I'm not snacking or thinking about food and I just ate my lunch which was soup. So I guess it's working. I don't feel any nausea or any other side effects, except for a minor headache.