I'm scared of the dark?

I don't know why. I used to be paralyzed of the dark because i thought there were witches or something. Now I don't believe in anything super natural AT ALL! Except when i'm in the dark. I feel like somethings watching me. Like one time so freaked out that I rolled up in a ball and fell asleep until morning. It doesn't really affect me when I close my eyes, but if i'm wandering around my house at night like if i have to pee or im thristy I shake, literally. It's completely unreasonable fear. I'm wondering if anyone knows anything that can help?