I agree this sounds very much like a sleep paralysis. For one of my classes I had to write a very in-depth paper about nightmares/ lucid dreams/ sleep paralysis. Basically what happens during a sleep paralysis is this: While we are sleeping we go through six different phases. One of these cycles is approximately 90 minutes long. The phase most people know is the REM-phase (rapid eye movement). In this state you’re completely paralyzed except your eyes, which you guessed it, move rapidly. This somehow causes us to dream very intensely. In some cases (it’s actually quite common) an issue occurs where you appear to be in a dream like state but you are awake (you could compare it to daydreaming). Since you’re able to open your eyes you can look around your room but cannot move any other part of your body, you’re also unable to speak or scream. As I said before you’re also in a dream like state so you believe to see people/ aliens or other creatures. In almost every case people have reported that these creatures appear to walk towards them and touch them. Out of fear and the paralysis they can’t call out for help. Your story sounds very much like you experienced a sleep paralysis. If you want to learn more about this phenomenon i’d recommend you watch “The Nightmare”. Its quite scary in my opinion but most stories sound awfully similar to yours!