I would say give the wellbutrin more time. Your body adjusted after the initial side effects and returned back to your original fatigued state. Wellbutrin is a stimulant but it works slowly like an antidepressant. Hopefully the positive effects will develop in awhile, giving you more energy without the jitteryness. It is also used off label for ADHD, but unlike other stimulants also takes a few weeks to begin working. Thus, non of those nasty adderall crashes.

Also, Wellbutrin can dehydrate you big time. Definitely look into drinking at least 8 cups a day. I have had a doctor tell me to drink even more when taking ADs. The dehydration could be causing the weakness and dizziness. At the very least, staying hydrated should help even if it isn't the cause.