I used to be terrified of the dark into my teens. At one point I got fed up of being so scared, so when I was home alone and the feeling got overwhelming, I just screamed at it as hard as I could and walked directly down a dark staircase where the feeling was coming from. It felt like my nerves were on fire for a second, but I think it helped get something to click in my brain because the feeling has never been so intense since then, and I can usually ignore it or just go look and calm down.