It sounds like your fear of the dark stems from anxiety.
Answer these questions if you would; why are you scared in the dark or at night? Are you fearing the idea that you're alone or are you just by yourself, left to do nothing but think while awake when no one else is?

I used to experience the same issue when I was about thirteen or fourteen years old, which is why I'm asking these questions.
Also, by any chance do you consume a lot of caffeine? Because I've also noticed that a good amount of it can also increase paranoia tendencies, which then lead to said anxiety moments.
I have an older brother who has some issues with anxiety attacks.

@Dmitri, that made me laugh actually, thanks