Okay so for a while now i have had this terrible night experience.

I will be asleep and its like my brain is being taken over, my whole body freezes and won't move, I'm awake but i can't open my eyes, shout, or anything its like being paralysed.
Then two images shoot into my head and its like unless i pick the right one my body won't unfreeze. it is the scariest thing in the world, and i feel so stupid mentioning it but i just don't know what to do.
Its made me fear going to sleep.
What is wrong with me??