I think I have paranoia...

I think I have paranoia, I'm not sure. I'm 16 I don't know what I'm thinking, I always think...or know..that people are watching me, or talking about me. just everyone, no one in particular. I think those people are talking about me, because there have been instances where a group of teenagers are talking, and when I walk by, one of them asks me "do you have any tattoos?" and I'd say no. and when I walked away I heard one of them say to their friends "dude, don't you KNOW who that guy is??" there have been tons of those happening lately. and I beginning to think that some gang is playing some game with me. the other day, I was walking beside the lake, and a gang of teenagers just walked pass me, one of them gave me an evil grin, like they're ready to pound me or soemthing. I don't even know them, I've never seen them before. and...I just have a feeling that everyone in the city is stalking me. even when I hear someone talk, I sometimes KNOW or feel or believe that they're talking about me. talking trash about me. I feel uneasy just posting this, because I think that one of those stalking me might read this, and tell the others that "hey, you know that "guy"? he knows we're on to him. what next?" I know someone's playing a game with me..or I'm just paranoid. I don't know, I do have depression as well, I'm very psychologically sick..I never seen a doctor or talked to anyone about this. and don't tell me I should talk to my parents because they're one of those whose stalking me. I know it, I just know it.