Seroquel and weight gain

I was prescribed seroquel 25 mg to help my insomnia as well as my depression/anxiety. I've been taking it for a week and I feel amazing! It helps me sleep and I no longer sleep until 4pm every day. Does anyone have experience with gaining weight with low doses of seroquel? I switched from zoloft to prozac because of the weight gain and I'm terrified of gaining it back. I've already gained some since my dad died this past summer.