This is Why There are Warnings on Meds, Kids

Today, tonight, rather, is Friday - and on Saturday past, I had a seizure.
The first seizure that I know of having. I say that because, as an ex-addict, it's more than likely that I've had at least one seizure before. Especially given which drug I was addicted to.
This was the first time I was at all aware of having had the seizure, though. I went to bed last Friday night feeling very... off. I don't know how else to put it. I woke up feeling just as strange, if not worse.I woke up Saturday and as the day wore on, quickly might I add, I started feeling notably not good. I was having a hard time staying awake sat on my couch, I felt nauseous, my head felt unbelievably cloudly... I just wasn't right. Eventually, I completely blacked out - which my boyfriend tells me was the seizure. Apparently, my eyes rolled back into my head, I was foaming at the mouth, I was convulsing, and I started off incredibly warm and by the end was shivering. When I came out of it, I couldn't find words and was speaking gibberish, and was incredibly nauseous. I actually puked twice, the last time being late Saturday night, closer to Sunday morning.
The next day, my boyfriend had me call my therapist, and when I ran into her on Tuesday, she told me to see my family doctor. So I did that, which resulted in another repeat of what happened followed by my being taken off of the Wellbutrin I'd come to love, having blood taken, and having to pee in a cup.
Yesterday - Thursday - I saw my psychiatrist, and he offered me two options: A) Stay off the Wellbutrin and just... see how things go, or B) get on something new right away.
Well, I wasn't happy about being off the only antidepressant to ever do much of anything for me, so I chose the latter option. My psychiatrist put me on Prozac, promising the possibility of weight gain was slim. I picked it up today, and I start it tomorrow morning.
I know there are going to be side effects, probably nausea. I just hope I'm able to go to temple - class and ritual - tomorrow, I missed last week because of the seizure, and it's something I look forward to every week.
I still don't know why I had a seizure. I haven't been purging - I think the last time would've been January at the earliest; and June marked my sixth year clean.
I'm still feeling residually tired and worn out.
Hopefully Prozac works out well for me.