Ever since I was a kid I've been horribly afraid of the dark. I have a very vivid imagination. I also read scary stories on the internet a lot which doesn't help, but I suppose I'd be just as afraid without it. I'm a fucking 20 year old straight man and I'm afraid as fuck of the dark. When I lay on my side with my back facing the edge of the bed, I think some monster is going to sneak up on me from behind. Or some sort of entity. When I face towards the wall, I'm afraid a ghost is staring at me. When I'm on my back I just stare into the darkness and think, "You know, A ghost could pop up in the darkness at ANY second." And when I lay on my stomach.....Well then they can just attack at all angles.
I have to sleep with some source of light on. A television, A computer, it doesn't matter. I can't stand being in the darkness.
IS IT NORMAL!??!
I have to sleep with some source of light on. A television, A computer, it doesn't matter. I can't stand being in the darkness.
IS IT NORMAL!??!

Your brain is telling you that is doesn't understand what is around you due to the darkness. So your brain goes into some mode where it starts "filling in the gaps" with all sorts of crap that scares the living out of you. I guess it's just a way of the brain telling you to be aware/or on your guard (a natural survival instinct).
I over come my phobia by realising that my imagination is getting the best of me.
Please also note that you must not be ashamed of your phobia as it is common among us adults. I find it sad that many people don't seek help is because the perception that you will be viewed negatively.
Please note that my comment is just from my experience and I'm certainly no specialist. I would recommend you seek professional help should your phobia continues. Thanks.
Are you keeping good sleeping habits? This includes no tv, computer or phone for at least half an hour before bed. Only use your bed (and preferably your room, but that's awfully hard) for sleeping and sexy times, not for lazing about on, studying on, or anything else. I'd also avoid those stories for hours before bed. I cannot watch scary movies, if I have to, then I do so during the day so by the time I get to sleeping it's not on my mind.
I'd also recommend buying a light with a dimmer. Start with whatever setting you're comfortable with. The next night, dim it a little lower until you're 100% comfortable with that setting. Keep going until there is barely any light and eventually, none. You just need to re-train your mind into what the dark means.
There are also amazing apps you can get for your phone which will play soothing noises, things from rain or waves to air conditioners and traffic.