I used to be afraid of the dark so I started to force myself to stand alone in the dark sometimes (you know the saying "face your fear") without moving and I don't like it but it doesn't affect me the same as it used to.
think positive for the whole day, don't even think about the night time. start a game when it's close to dark, you'll be having fun, so it will seem less scary when it does get dark. Which you have to realize it does every night-get dark. Think to yourself, "why am i so scared of the dark?" and maybe write down a list of reasons and talk them over with your mom. You'll realize there's really nothing to be scared of. nothing at all. Tonight, sleep with your light turned off. Even if you get scared, leave it off. You'll wake up in the morning and it will be a new day and you'll realize that it wasn't that hard, and nothing terrible happened. Good luck! And have fun on Wednesday. there is nothing to be scared of.