I once had a sleep paralysis experience I now empathize with those who believe that they were being abducted by aliens, well , because it damn well felt like it the time.
It's an interesting experience of being unable to move, hearing really loud and high pitch tones,the feeling of being pulled upwards; all coupled with a terrible sense of something foreboding and close.
Not to mention the fact that you are shitting yourself with fear. I remember telling myself over and over that" this couldn't happen, aliens aren't real" 30X over.
Then I was awake, looking at the ceiling and still unable to move for a further 15 seconds or so. I can tell you right now, I did not go back to sleep.
If you were less wise than your truly, it is entirely conceivable you didn't go straight on wikipedia to work out, in my words , "whatever-the-F**K-that-was".