ghosts

Something happened to me last week that changed my belief in ghosts, because I think we have one in my house. The reason I say that is because I  saw something one night in my room and it was not my mom or dad .  It was a shadow and when I blinked my eyes, it went away fast. Now, when ever i go in to my room or my mom and dad's room I feel like someone is watching me and it freaks me out like someone is going to come out from out behind me and hit me.  Has this ever happened to you?  What do think in terms of ghosts being real or not real?  Post your comments.