My Imagination?

I feel regardless of where I live my houses are haunted. The previous tenant of my current residence did pass away in my house shortly before I moved in. While I have never seen anything I have experienced many things in my house such as lights turning on and off, doors inexplicably opening and closing, rustling in unoccupied rooms, and objects being found in odd places. I am often depressed in my house and find it hard to even move sometimes like something is weighing me down, I also get bone chilling cold for no reason at times. I have always felt even when I was younger like I was being watched through windows and hallways scare the crap out of me. Am I just crazy? Shortly after moving in my oldest son tells me that the man here says to be nice to the kids. Both of my children are often found conversing with someone who is not there and while I know that if they are not frightened I shouldn't be I had a disturbing dream the other night. In my dream I could feel something drawing me into the closet by my front door which has been known to open and close on its own. Upon examining the closet I was shoved back by a frightening force and whispered my best friends name Bryan. I remember in my dream I was terrified like he was trying to scare me. Bryan has been dead for 7 years now and I know that he would never frighten me. His wife and I remain the closest of friends and feel we are bound together by Bryan. Those 2 were soul mates and she knows he is there in her times of need guiding her through life. She tells me to ask him for help but I don't know how or if it is ok as a Christian to invoke a spirit, good or not. Also I question my importance to him to stick around me when she is in need as she is right now. After this dream I am afraid this thing is not as good as I thought. What do I do? How am I sure if I do make contact, if I can make contact that it is Bryan? And how do I make contact with him? While I know I said I was Christian I am very interested in paranormal activities and always have been. I just want to know how to keep myself safe.