I have nights too where I'm absolutely terrified to sleep in the dark (although I hate admitting it). When I get absolutely desperate during these times I leave a very dim lamp on in my room at night. I want it to emit just enough light to let me clearly see everything around me but not much more (more than a night light, less than most lamps)- a comforting and relaxing light level. I always sleep with a ton of blankets and I will pull the blankets over my face if I need darkness for sleep, but whenever I start to feel uncomfortable I easily lift the covers and have immediate light. Sometimes I'll leave an area open in the blankets so I can peek through and let a bit of light in. It's easy to adjust based on what I need at that particular moment.

It might also help to have someone with you. A pet, perhaps? Something to keep you from feeling alone. Of course, any animal you bring might make some noise so you'll have to evaluate for yourself whether that would be helpful for not. I've also grown accustomed to having something to grab onto as well - like a stuffed animal or body pillow. Sometimes that can make me feel more secure as well.

The last thing I do is lock the place up before bed. There are people who will testify that I will not sleep with an open door. If the bedroom door can be locked, I want it locked. I get everything I need for the night (water, etc) and barricade myself in. However, I also know people who feel better having the door open because they feel trapped otherwise. So it's all about how your mind works and what makes you comfortable.