I am 5 ft 160 lbs age 56. I started Belviq 5 days ago. There is no change in my appetite. I have been very tired since going on it. I am on Wellbutrin. Prozac and Cymbalta. My Dr. Said to go off the Cymbalta, which I am tapering. I have 2 questions: 1. By when should Belviq start to work? I have read about so many people feeling the effects shortly after starting it.2) could my lack of response and extreme tiredness have to fo with interaction effects with my medications? Thank you for any help you can provide. Lisa.