I do the same thing with the blankets over my head and I get scared when my head is exposed. I also can't face any doorways or open spaces, I have to sleep facing a corner, a wall...something. I keep opening my eyes to check too...reading your post was like reading something I would have wrote...wow.

On top of that, I also have a fear of mirrors or anything reflective while it's dark. I have a reflective piece of clear vinyl covering most of my door to the hallway in my apartment...I don't know why it's there, the landlord probably did it, so I don't take it off. But it freaks me out knowing I could see my reflection if I lift my head and look in that direction. And then there go the blankets, over my head, and my heart starts pounding and I have to remind myself it's just my mind running away again.