I had the same problem when I was living on my own. Every door had to be closed, even closets. I had to have a light on. I was on the third floor, but locked the porch door even though you'd have to be spider man to break in and hurt me that way.

I started to feel better by falling asleep to people talking. I fell asleep with radio or podcasts on every night. I would also sleep with the phone next to me. I also had pepper spray next to me. When not sleeping I would usually have the TV on. Calm voices feel safe to me. Maybe that could help you a little.

Other than that, I guess it must just take time... that's what helped ease my mind.

I wish you good luck, though!