I hope going off meds works out for you. I'm bipolar and I've been on various meds, including lithium and Seroquel. I never felt they blocked my creativity directly (I write, too, fiction and non-fiction) but I did feel kind of flat and unable to enjoy anything while on meds. I don't know if it was the meds or just the depression shining through. The major impediment to my creative writing has been the depression itself. It takes away my confidence and makes me second-guess every thought I try to put on paper, to the point that I don't get anything done because in my mind, every sentence I try to write sucks. I think it's more of a depression-induced self-esteem/motivation issue than a lack of ideas in my case. I'm getting ECT at the moment, so hopefully I'll soon be able to finally release all these pent up ideas that I've been collecting for over a year now!