Is it normal to be afraid of the dark still

Ok so for most of my life, I've been afraid of sleeping with the lights off in my room even though I'm all grown, I only feel comfortable sleeping in the dark if there's school tomorrow or if I'm going somewhere tomorrow but during the weekends I'm always afraid to go sleep without the lights on, always afraid of something bad happening to me, a sense of weird paranoia enters me or something, I don't know why I've been like this since I was little and still like this today? I don't know why, this can't be normal?