Is it normal to feel a presence nearby?

Do you believe in ghosts?
I sometimes feel a presence anywhere, in the house and in public.
A week after my cousin's death I felt someone lay in bed with me. I felt the dent or whatever beside me. Then I saw a dark shadow.
I also seen a a white shadow in corner of my ceiling a few weeks after that night. I saw wings flapping.
This one time on snapchat I used the one eyed filter and seen a head in my eye.
Another thing is, I was home alone and a door was opening but the windows were shut and the ac wasn't on.
Lastly, I was watching tv in my room with my cousin and a big straw hat that was not close to the edge of our closet felt perfectly flat on our hamper.