I have been on Wellbutrin XL for almost a month now and I feel fine. The first week I took 150 mg. and had problems sleeping a few nights, and felt a little hyper at times and felt pressure in my chest sometimes. After about 5 days I was adjusted and felt ok. Then I upped the dosage to 300 mg (the full dosage) again I felt a little strange and had a horrible migraine like headache for 2 days but again I adjusted after about 5 days. I think this is my 4th week and I feel great! I haven't put on weight with this one and feel totally normal. Really I think this is the best one I've tried and over the past few years I've had to try different ones which side effects I couldn't deal with.