I think I might be haunted

I am in desperate need of advice please. Since I was very young (around 6) I have felt as though something has been following me. My brother and my sister also feel as if something follows them as well. We had a tough childhood, got put into foster care when I was eight years old, and I was abused most of my childhood, whenever I have spoken to therapists about this, they tell me it is all in my head. I dont believe this for a second, I know I have been abused and all, but I do think that these things I experience are real, and I am sick and tired of being afraid! It started out when I was six years old, I would see things, and hear things, people calling my name and the ghosts of people who had passed who were close to me. Being in foster care I always moved around, even to different states (foster care system kept trying to give me to family members after my mom lost custody) and everytime I moved it would start out fine, but get worse and worse the longer I stayed. Everywhere I went I would feel as if I was being watched, things would happen (I felt things jump on me in the middle of the night, my voice being called, people crying out for me to help them, being touched on the leg or foot while I was sleeping, and horrible nightmares about demons) I finally stopped moving around when I was 14, I got adopted and went to live with my new parents. Right away things started happening to us, my younger brother (who was to be adopted as well) tried to commit suicide and told me later that he heard voices that told him to hurt himself (right after that his therapist put him on meds for schizophrinia (SP> a week later my older brother (who lived five states away from us) tried to commit suicide as well and was also put on medication. My older sister (who also lives far away) experienced hearing voices and seeing things, and so did I. As I got older I moved away from my parents house into my own apartment, and I couldnt spend one night in that place by myself, everynight I would have horrible dreams, and the airmattrice I slept on would always be moved around when I wasnt home. Then things started being moved around (pillows, my bed, things in my bathroom, even my fridge door kept opening up by itself) Almost three months after living by myself I got severely depressed and was admitted into a psch ward, it was horrible there, I couldnt go anywhere without feeling like there where spirits everywhere, and they were worse, almost evil. I would break down and they had to keep me in a seperate room before my parents finally convinced them to let me out. SInce then I have felt followed by and evil spirit of some sort, and even my friends tell me they feel it to, they see things, hear things, and one of my friends (who is wiccan) was choked. At that time I was living in my own house (i was 19) things got worse and worse, I felt and evil spirit in my basement where I kept my cat's things (food and litter box, so she was almost always down there) and it got so bad I wouldnt even go to the basement, soon my cat wouldnt even go down there. I found renters for the house, and moved out of state. I am 21 now, am married and I just had a son five months ago. THings started out okay this time, but we just moved into a new apartment, and things are bad again. I have horrible nightmares of demons and I can no longer sleep without my husband in the room, and I fear for my son. I always pray everynight and something tells me that this spirit cannot hurt me unless I am afraid, but I am afraid, and I am afraid for my son. What can I do to get rid of this spirit? I have been told multiple times that I have some sort of connection with spirits, but I dont know how that is possible, please help!!!! is there anything I can do to make this go away?