Shake, Rattle, and Roll at 4 A.M

*BANG* *BANG* *BANG* "What is that?" I thought as i turned my head in bed. "Oh the bookshelf is moving.....THE BOOKSHELF IS MOVING!" I jump out of bed and rush to the door frame standing in place. After a few moments the ground settled down. I waited a few moments and went back to bed. When I got up I wondered if I dreamed the whole thing until I got to work. Everybody was talking about it and to add to the creepiness it happened again at work. I guess I need to be more alert for the time being.