Confusion

BANG. BANG. I bolted straight out of bed, rubbed my eyes and glanced at the clock, 12:45 am. Dang. I stand quietly in the dark watching, listening. All is quiet all seems well. The only thing I can hear are the subtle noises of sleep (my son moving around on the bed etc..). Slowly and silently i began to move about the house, check on my kids, check out the windows, check everything, and I find absolutely NOTHING. I let the cat out (darn cat), I check the windows again. NOTHING. Slowly, wearily begin to creep back to bed. My sleep ruined, on edge, curious....Wondering.

Now I tell you that I swear to you, swear to you that I bolted out of bed because I heard (or thought I heard?) (or dreamed that I heard?)someone knocking at the door..
Weird!