Happened to me a few times, scared the fuckin shit out of me cause there were hallucinations accompanied with it usually when it happened... One time it felt like a bunch of people were pacing around my room just beyond my sight, breathing and mumbling... I couldnt move I thought someone had broken in and had me bound and ready to kill me. When I regained control and woke up fully I sat there for like 15 minutes in a cold sweat shaking.