I get that feeling from Seroquel. I have to take cogentin to counteract it. However I only use Seroquel in a severe episode so I haven't had to take it for a couple of months.

My question is are you otherwise calm? Like, are you having symptoms of mania still - racing thoughts, high energy, etcetera? If you still have symptoms of mania and also symptoms of depression then it's a mixed state. If you're otherwise calm, i'd blame the meds.