I feel like that ALL THE TIME! although for me, it started after I had a bad trip on acid. Weed can make you hallucinate, I think that's where the paranoia comes from, try just smoking when you're around other people, and if you still feel the same way then quit smoking. or try not smoking as much, but I know what you're talking about, that like going insane feeling, it blows, really fucks up your high.