I havent read back since last night but I'm a big proponent of mental health and tricks to get your brain to cooperate. If that's not your jam, feel free to skip.
First off, if you have internalized the idea that you being scared is unreasonable and are beating yourself up about it or feeling mad at yours or ashamed or anything, that's another layer of icky you have to deal with on top of the actual fear. As many people here said, being afraid of the dark IS a common reasonable thing. You arent weird or broken. Your apprehension would probably have been a sought after characteristic in evolution when people who went out in the dark DID get mauled by night predators. You would have stayed home and lived. Having leftover instincts from eons ago isnt unreasonable. Look at chickens - some breeds have a lot of predator awareness still and some have adapted to being house pets. While the predator awareness seems unreasonable if they live in a fort Knox coop, it's totally reasonable and sought after in free range birds.
So forgive yourself for being afraid. It's okay and natural.
I have a lot more to say but I gotta go for an hour aha. BRB.