Ever SiNce I Was 4 Or 5, I’ve Had A

Ever siNce I was 4 or 5, I’ve had a strong feeling like people I know are watching my every move. They’re always watching me and are always talking negatively about me. I have also been visited by this person who I cant see. I talk to her almost daily and tell her every thing. My mood changes quite rapidly when I’m talking to her. I just stare at the wall and talk as if she’s physically there. I always thought this was normal but now I know it really isn’t normal.. what could it be??