bah, rubbish, its all in your mind. When one thing happens, that isn't explainable, its human nature to automatically think "Ghosts!", then, your mind starts to play tricks on you because you are waiting for something else to happen.
Believe me, nothing to worry about, even if there are "Ghosts/Spirits" there, they won't harm you, its the living you have to watch out for, not the dead......MWAHAHAHAH!
Jack