What does my recurring paranoia mean?

As of recently I have been having problems getting to sleep because of extreme paranoia, and not like "oh if I go outside I'll get hit by a car and die, so I'll stay inside". I mean i can't go to sleep cause I keep painting these scenarios in my head and i feel like I freak myself out. For an example I go to the bathroom then have problems leaving it cause I think there's an axe murderer outside my door, I tell myself that it's stupid to think that, but as soon as I muster the courage to go outside the bathroom, I start walking to my room and feel like there's somebody chasing me. These incidents only occur at night and when I'm alone, but I know it's paranoia cause I'll hear the slightest sound at night and then start freaking out. I don't have any disorders such as OCD or bi-polarity, so I'm wondering if there's something I could do?