Paranoia is an irrational false belief that you will be harmed by something that can not happen. "The CIA is trailing me and trying to frame me as an Al Quaeda agent". Paranoia sort of overlaps with psychosis - You can be paranoid about a delusion "Martians are trying to frame me as a spy". I guess I got that right.

Hypervigilance can have elements of paranoia, well, the flavor of paranoia. But it is a fear of something which is possible, although unlikely. Someone who was attacked by a pack of pit bulls that got loose is unlikely to be attacked again in the same way, but still is very fearful and constantly on the lookout for dogs."

Not really a good idea to walk around with weapons. I did, once, albeit in the middle if the night and in a pack until I intend to use it on myself. But, I could have been arrested and charged with a felony or even been shot by a cop under the most extreme scenario.