Could I Possibly Have The Gift Of Being A Medium?

I've joined this site to seek help and advice from more experienced people. I've always felt a "presence" around me, like someone's always watching. Even when I'm in my room alone trying to sleep or I'm in the shower, I always have this paranoid feeling, like the feeling you get when you know someone is staring at you. I've always thought I was just crazy or something, especially after experiencing seeing shadows, figures walking past my bed room window, voices, etc. I just now started seeing this amazing therapist and she told me that I might have a "gift" of some kind. My experiences are quite strange, also. The three most vivid ones are the following:

*When I was around three years old, I had an imaginary friend, Michael. I don't remember anything about him. Just this one story that my mother told me:

One day, my mom was walking into the living room after sending me to my room because I got in trouble for making a mess in the bathroom or something. She heard me from the stairs talking to someone, and this someone just happened to be Michael. I was shouting at him telling him "No! I won't!" My mom walked up and asked me what was wrong. I told her that Michael wanted me to shoot her. Now how does a three year old come up with that? To this day, my mother and I still think Michael may have been an angry spirit.

*One night I had locked my cat in my room and I walked upstairs to get a pencil. As I started down the stairs after retrieving my writing utensil, this small dog sized shadow shot up the stairs scaring me half to death. I turned around and ran upstairs following whatever it was. The dog saw it too and chased it into the laundry room. I went in there to find the dog barking at nothing. I looked in the kitchen and my cat, Bandet, was sleeping on a chair. I ran to my mom's room and my other two cats, Babygirl and Punk, were lounging on my mother's bed next to her. And our fourth cat, Bugsy, was still shut inside my room. I still don't know what it was that I encountered that day.

This one is short and not as weird as the others:

*I was cleaning up after my 13th birthday party and my mom told me to go downstairs and get the trash can. I went in the first room of the basement, and as I bent over to pick up the trashcan, I heard someone very clearly say "Hello." I wigged out and ran upstairs because I was so freaked out. My mom never has believed me though.

I'd really like some advice, because I don't know if I may be a medium or not. All I know is that I'm a pretty terrified fifteen year old that desperately needs help and advice!