Wellbutrin & Smoking

I am currently taking wellbutrin-sr, (2) 150mg pills per day. I am taking this to stop smoking. This is my 2nd week and I have only been smoking like 1 cigarette per day for the last 2-3 days. Today I have smoked none. I am feeling very weird. I am shaking, kinda dizzy or lightheaded, and sometimes I can feel my heart beating faster. I didnt know if this was the medication or not, so I called my doc, he told me to cut down to 1 pill a day. Do you think this could be a side effect of the medication? I almost passed out at a festival I attended a few weeks ago, my heart was racing so fast the medics couldnt count it. I dont know anyone who has quit smoking with wellbutrin and I am wondering if they felt the same way? Also, is there anyway to lessen the effects of withdrawal? I really wanna quit.. But I feel like crap!

thanks

aerogurl