Why if you tell your doctor that your 150mg dose of Wellbutrin is working for you and that you are doing well on it, why would he double it to 300 overnight? No slow increase for side effect control?? And what is 300mg Wellbutrin XL going to do to me all at once?? I'm pretty scared. I can't not take it cold turkey. Anyone else experienced such a rapid increase so quickly? And no reason explained to me.