I live in a small house near London with my mother father and two sisters one older and one younger. My sisters share a room and in this room are two single beds. One weekend my grandfather came over from Ireland. This was rare as we barely ever saw him. During the time of my grandfathers stayed he slept in my little sister's bed and she slept in my room on the floor. On the first night of my grandfather's stay I fell asleep as usual as did my sister. At around 1 am I would say, I was awoken by a sharp hissing sound, I slowly opened my eyes and turned over towards the door and to my shock I saw a small girl standing at the door fully dressed in white. This at first didn't scare me as I naturally assumed it was my sister getting up to go to the toilet. As I looked down to see if it was her, I saw that my sister was fast asleep on the floor. I looked up once more to see if I had actually seen what I had seen and I still saw the small girl standing there. She had a glow about her which scared me. She was fully clothed in white with some form of head wear, almost Victorian like. I closed my eyes as to dismiss this girl but as I opened them she was still there. I did this one more time and when I looked again she was gone, just like that.
Since that day I have always been cautious of my house and have had around half a dozen experiences in my house where I hear things during the night and some times see shadows fall across my room.
Can anybody tell me what this could be or how I can prevent these things from happening?