Wellbutrin and three months

I started taking 300 mg wellbutrin sr while weaning off of effexor xr (another nightmare) about three months ago. The past few weeks I have been extremely agitated with everyone in my life. I have also had the worst migraine of my life that will not go away. I'm not sure if this is a side effect of the welbutrin, or just more painful effexor withdrawal? My husband swears that my anger has made me a different person. I hate the way I feel, but don't know if the Wellbutrin is making it better or worse. Anyone have any input?

This is the 3rd time I have been on Wellbutrin. Once in 1999, then in 2004, and just started taking it again 3 months ago. The first two times I took it I had joint pain and a lot of muscle inflammation. This go around is different... Just recently, within the past few weeks, I started breaking out with hives, after taking it with no problems for three months! Started on my head and progressively got worse. I break out all over my body, head, legs, back, hands, etc. For some reason it seems to happen more frequently when I lay down in my bed to go to sleep (weird!) One other scary side affect is, I frequently stop breathing when I start to fall asleep, and wake up gasping for air. Has anyone else experienced this?
Since I had never experienced problems with hives the first few times I was on Wellbutrin, I didn't think it was the medication causing the hives. So, I cut my dose in half (50mg/day). The hives didn't go away, so I stopped taking it all together 3 days ago, but still continue to get hives. Does anyone know how long it takes to get it out of your system?