I'm still afraid of the dark really. I run past dark spaces in the house lol. I don't think "I'm in danger", I just feel uneasy and hypersensitive to the "energy" (used to be spiritual, now I understand the physics) around me. I usually leave the TV on when alone to drown out the other house-sounds, and need pressure like a heavy blanket or pillows.
I find my visual sensitivity is heightened in the dark, and it looks like an old TV screen with no signal- pixelated sort of, so my brain can go wild noticing patterns in the dark. I think that's why it's scary, but only realised this when I found out about aspergers. Have you tried identifying and "treating" your sensory issues, like having a weighted blanket, radio on, small night light projector (you can buy on sensory websites), and just forcing yourself to be alone for a night? It would depend on what you think might help you- try different things until something works. I think when you face your fears its never as bad as you thought!
When i was a toddler I saw a news story about someone who drowned at sea, and it explained undercurrents- I can still remember the visuals. My family say I suddenly became terrified of the sea, and remember thinking the adults didn't seem to care about checking the tide and subsequent undercurrents lol. Obviously I couldn't verbalise this at the time haha, but I never talked about my fears to anyone anyway. I just tried my best to get over them. Ironically, I surfed for a while in my late teens and absolutely loved it- I had checked the tides!
Also, I was scared of tiny spiders because they used to attack everyone on the school field. Big spiders were fine because I knew where they were!