Seroquel can cause "metabolic syndrome" which basically messes up your metabolism which can contribute to weight gain and difficulty losing weight. Seroquel effects histamine receptors which cause the drowsiness and the weight gain. Once you are off of it for about a month I would guess you'll find it much easier to lose weight. It takes a while for the med and its metabolites to clear your system. And if it was causing metabolic syndrome, it will take a while for your system to re-adjust and return to normal.

So hang in there and try to be patient!

Jerry