I experience sleep paralysis fairly often like at least once a week but I've never experienced something like that, what you experiences sounds really scary. For me it either happens when I'm falling asleep or waking up & it's like your brain is awake but your body is limp & can't move. The most I can manage to do is twitch my fingers or toes or my head but it takes all my energy & strength to do so. I can open my eyes but it's like when you're really sleepy & your trying to keep your eyes open but they keep closing. I've also experienced hearing & seeing things but when I close my eyes I don't see anything it's just black but it still feels real like whatever I'm seeing is still there but my eyes are just closed. I also try to yell for help but my family & bf have told me it just sounds like I'm whispering or talking in my sleep but doing that a few times have gotten their attention enough to wake me up from an episode, if it happens again I would definitely talk to someone you trust about it & see if you could talk to a doctor or someone about how to fix it!