How many people have been killed or seriously harmed by ghosts? None, I can tell you there are no recorded scientific accounts of ghosts causing harm to people; let's put it into perspective, with spiders or snakes as a phobia it's a concern in many countries that you could be seriously harmed by them, so the phobia is somewhat more rational, With ghosts? But then a phobia wouldn't be a phobia if it was totally rational.
OP your not strange but your fear is certainly not based in reason. Try the tested method of exposure to your fear, watch The Exorcist or The Thing, or the Ring, a few times, or force yourself into situations that make you fearful like walking around in the dark, it sounds like a real nightmare but I'm sure you'll much more quickly get over your fears by facing them, than by imagining them all the time.