Unusual Encounter

Is there such a thing as ghosts? I think this question has been asked since the dawn of civilization. Well, honestly, I have not seen one, and hope will never! However, I do believe there is such a thing. I recollect one strange encounter when I was a small child around the age of 5 years, or thereabout (I couldn't remember exactly).

I remembered that at that time I was very sick then, with high fever and that sort of thing and almost felt like dying, sleeping most of the time. One night while sleeping I was awoken by some strange very loud banging noise on the door of the room next to my parents room in which I was sleeping. The banging was incessant and absolutely very loud and it sounded as if someone was desparately trying to get out of a locked room. It came in a sort of rhythmic banging.

But very strangely, despite the loudness of the noise, both my parents were sound asleep as if nothing had happened. I then realised that it was I alone who could hear this sound. I was so scared that I dared not opened my eyes for fear of seeing something fearful. I tolerated the noise and very soon I got so tired and fell asleep. When I got up the next morning I dared not even walk pass the room. Slowly, after a few days had passed by, I bravely went and inspected the door but found nothing unusual - no damages or whatsoever as I expected to see, at least, something if someone was banging that hard!

Up till today that thought still haunts me even though I had not seen anything hideous, but the incessant banging noise still lingers in my memory.

Is what I experienced was simply a hallucination of the mind when you are very sick, or what?