Why do strange things keep happening to me?

nearly every time i sleep in my sisters room something strange happens, ive hallucinated things crawling up the wall, and also on two separate occasions ive saw men standing at the bottom of her bed. Im awake just now at 4am because i cant sleep because of what just happened. I opened my eyes and saw a black swirl in the corner, where ive saw shadows before, then my vision went totally black and my body stiffened and shook, and my sister woke up because i was grabbing her and saying her name. This is starting to scare me, has anyone else experienced something similar?