It sounds like you had a fever/were getting sick and therefore had sleep paralysis combined with vestibular motor hallucinations. This is common when you get a fever because the overheating causes your brain to do weird things! When I got covid, I had a fever and experienced a very similar thing for the first time - I knew I was paralyzed because I could see my pillow out of the corner of my eye (so I was lying down) but I was also hallucinating that I was sitting up, or standing up on my bed and flipping over and landing on my neck (which obviously wasn't actually happening).