I took 50 mg of Pristiq for about 5 years and I felt like it wasn't working anymore. I asked my doctor about Wellbutrin because I had read that you can lose weight and have no sexual side effects. I started about a 5 days ago and I feel kind of nausiated and when I try to sleep at night my heart feels like it is racing. Has anyone had these effects and will they go away or should I call my doctor? Any help would be greatly appreciated!