I think there is paranormal activity in my house?

i live in a 3 roomed house in stoke with my dad, step-mum, step-brother, step-sister and my real brother. In my room i took a picture of my reflection in the mirror for a Bebo photo, but later realised there was a black ghost-shaped thing in the mirror. Also we have experienced random phone calls with no answer, and objects being moved SOMEONE HELP!