Do I have paranoia? What should I do?

Do I have paranoia? I am 13, and since i could remember, i have always been paranoid, but i thought it was normal or that it was my ADHD. recently, my teacher mentioned paranoia, and i was wondering if do i have paranoia? Or is it my ADHD? this is how i feel everyday: i always feel like someone is watching me, even when I am completely alone,i even feel like someone is in my house sometimes I always feel like people are judging me, when I hear people laughing, I automatically think they are laughing at me or about me, when they aren't, I don't really talk to anyone besides my friends (who don't know about any this). I feel like my friends are trying avoiding me, or they hate me (even though they don't avoid me, or show any signs of hating me). I hate being around people, and when I am, I usually just want to run away. Am I paranoid? Or blowing things out of proportion? What should I do?