I near shat myself...

My parents were away on holiday, when they are away I check all the doors in the house are closed and locked before I go to bed. I was walking from the bathroom to my bedroom which is just a few steps when NO JOKE- The door of the spare room opened!! It was one of those times when your so scared it hurts! I plucked up the courage to push the door open wide... I couldnt see anything so further in a went... still shating myself I turned the light on [It was like one of those horror films when you just know they shouldnt go in] Thankfully nothing there. But how freaky is that? The door opening when it was tight shut?!