This used to happen to me all the time and it was just about always coupled with the same hallucination, a completely black "shadow man" approaching my bed or getting in the bed with me.

The first time this happened to me was in my teens. I was home alone. I woke up but didn't open my eyes at first because I felt a presence in my room. I cracked my eyes and saw a black figure walking across my room. Of course this scared the shit out of me because I knew no one was home but me. My mind raced as I thought about who it could be, how they'd gotten in, why the house alarm hadn't beeped, and in the couple of seconds while I was thinking about this the black figure climbed in the bed with me. I could feel the mattress depress and shuffle and everything.

Now I was really panicking. I didn't know if this person was going to stab me in the back, attack me, I had no clue what was going on, but I knew I had to act. I've been involved in martial arts for most of my youth and I had a sword at the foot of my bed, but in that moment if felt like it might as well have been miles away as it felt like I was going to be pounced on any second. So I figured I hit whoever it was first to give myself time to grab the sword then hopefully fight for my life before I was killed. So I spun around striking with all my strength into an empty bed.

Soooooo yea, this was a totally traumatizing experience, and it was months before I was able to sleep well again. I didn't hear about sleep paralysis until more than a decade later as an adult and I thought it had to be a ghost or demon, and I hadn't even before believed in anything like that, but that experience made me a believer.

Over the years, this happened several more times, but I sort of got used to it, and found a hack that if I fell asleep with the TV on it didn't happen, but umm yea...cute cats :)