Could Nausea And Dizziness Be The Side Effects Of Bupropion?

I have been taking 150 mg of bupropion for 3 weeks as a replacement for Celexa. I have fibromyalgia. I have also been taking Lyrica for approximately 3 years and I have gained 25 pounds. I am concerned about the weight gain and the doctor and I discussed replacing the bupropion for the Celexa since it has a side affect of weight loss. I started with worse joint pain in my hands and feet. I am also getting nauseated in the late afternoon, and dizziness with a migraine. I am 56, female and had a complete hysterectomy at 42. Could this be a side effect of the bupropion? How can I lose weight while on Lyrica?