I m 18 and i have been severly paranoid for as long as i can remember, as a child i rarely spoke, and as the years went by i developed extreme anxiety , and depression . My mood goes from being extremely hyperactive, to crying my eyes out for no apparent reason, to so angry that i terrify my parents, even though i dont Feel angry at all. i have conversations in my head all day every day, basically non stop. I used to be an A grade student, but now i find it hard to even concentrate on a book i m reading. I have tried to kill myself many times, and i dont know what to do. Please help me.
GO SEE A PSYCHIATRIST is my first advice.  I have a rule of thumb that anyone who has so much enough contact with reality to say "I feel paranoid" is not actually gone into the pure psychotic state that the thoughts can be called Paranoid. In my experience only chronically psychotic people have had that experience to recognize their paranoia and state so...not an 18-year-old (I guess you have not been chronically psychotic, right?) Your symptoms are suggestive of severe depression and hence my advice is again GO CONSULT A PSYCHIATRIST GOOD LUCK