Is it sleep paralysis?

Last night I went to sleep at 12 midnight, I had just closed my eyes when I had a nightmare. I heard a rustling on the window then suddenly there were silhouettes on the side of my bed, there were a lot of them and I heard them chanting something. It was like a cult movie. Then I suddenly felt a very strong vibration in my body and I felt like I was floating upside down. What could that be?

btw by 12:30 I had 3 nightmares. My roommate just woke me up.