I have never tried the brand-name Wellbutrin so I have no point of reference.
Within days after my doctor started me on Budeprion I felt like I had the flu but my temperature was normal. The intensity of the symptoms varies from day to day, but I have called in sick a couple of times (something I rarely do).
I called the doctor and told him what I was feeling. He was skeptical but told me to go ahead and discontinue the Budeprion. I'll bet I start feeling 'normal' again.