Under The Bed Covers

I was having dinner in my room when a lump popped up on my bed at first i thought it was my sister being stupid but it was much bigger. i got really weirded out so i closed my eyes and said i was being silly. when i opened my eyes this bloody scary monster was blinding my sight it wasn't like it was in front of me it was like i had my eyes closed and it was haunting me. when i screamed for my sister the image was gone...

what happened to me?....am i going mad?...What does this mean?