Flying Sheets

This happened to me when I was about 12 years old. I'm 22 now and to this day I still can't explain what happened to me.

I was lying in bed one night trying to go to sleep, and I remember that night because I couldn't sleep for some reason and usually I pass out in about 5-10 minutes. So I was lying there with my eyes wide open, when all of a sudden all of my bed sheets, blankets and covers flew off me almost as if someone tore them off from the bottom of the bed. I was so terrified I just laid there silently for about 5 minutes until I finally ran out of the room screaming for my parents.

The odd thing, though, is that I went back in there to sleep the next night, and nothing. Nothing like that has ever happened to me again since.

Before then, however, when I was around 6-10 years old I heard a voice calling my name on many different occasions that sounded like my grandmother. It was always very late at night and I was trying to sleep but couldn't. Whenever I went to her room she was always either asleep or told me that she hadn't been calling my name.

I have no idea if these events are connected but it always happened when I was trying to sleep but couldn't. Normally I'd say it was an overactive imagination when I was younger but the sheets flying off the bed were very, very real. I know I was wide awake when it happened. It was definitely not a dream because I remember everything vividly, and I remember running to my parents room when I finally gathered enough courage to leave my bed. But nothing's ever happened since, and weirdly I've never been afraid of whatever it was even after the sheets flew off me.

Any thoughts?