I can't stop touching things?

Ever since I can remember i've always felt the need to touch things. No matter what i'm doing, I always have something in my hands. I go out of my way to take the little round pieces of plastic under the cap of a water bottle to play with it, or I rip leaves off trees as i'm walking by so I can rip it up. It's at the point where once I start doing it, everything else i'm doing becomes irrelevant. I can't stop. I need to feel my hands doing something or I start to breathe heavily and feel really uneasy. I've ripped up important pieces of paper, and broken zippers off my clothes because I just furiously touch things ALL THE TIME. I just want to know if anyone else has had this problem, and if/how they've fixed it? This has become such a bad problem. Please help :(