As a child I used to hate going to sleep when I had a fever. Sometimes you get to experience this really unpleasant sensation of impending doom and emptiness, your muscles go numb, your fingers become hyper-sensitive, the room begins to spin, you shrink in size and it usually ended with some sort of audio hallucianation,as if someone was screaming or whispering into your ear. Creepy as fuck. I sometimes get to experience all this even today when I go to sleep really worried or streesed out about something.