Scared of the dark. Really serious?

So I'm 15 almost 16 and I am extremely afraid of the dark. Mainly of that exorcist girl. Every time I try to fall asleep I see her in my mind and right now it is 1:36 AM and I keep looking at my left if anyone is staring at me. I sleep with the TV and that helps a lot! However every time I shut my eyes I have to open them every 30 seconds to see if anyone's there. I keep telling myself "They aren't real. They are fake. Never believe them.." It doesn't help.. I even think of happy thoughts and nothing helps.. Which is also a problem for me in going to sleep.