Yes, cut back very very slowly, I'd say more than a few days, maybe like 3 weeks? And see your doctor every week.
But since he's putting you on welbutrin while weaning off zoloft then that should help a little bit. Wellbutrin is a stimulant though so be prepared for some insomnia the first week.
I would recommend being very very careful when coming off Zoloft, I stopped taking it cold turkey and I regret it. I can't drive at the moment because I keep getting numbness in my legs and feet, I have had to pull over 3 times this week becuase I could not get my foot to move to brake at stop signs and corners, VERY DANGEROUS. I've had to pull over and use the hand brake to stop the car.
I have been on Zoloft for about 6-7 years, I was put on it because I was having severe panic attacks and made a suicide attempt, I tried to come off it because I thought I was ok. But the panic attacks have returned (severly). The withdrawal symptoms have been a complete nightmare, dizziness, nausea, panic attacks, headaches, uncontrolable shaking, numbness and fatigue.
My advice would be to cut the Zoloft back very slowly, and keep in close contact with your doctor. I can't help with the Wellbutrin cause I have never been on that one.
I sincerely hope that everything goes well and you can get off the Zoloft without the god awful side effects that I have been having.