I know how you feel bro I definately do but, its not worth it. I've been through the same thing. If she can't see how you feel about her and would rather be with that douche then she's not worth it. Relax bro, compose yourself and gather your thoughts; dont let your emotions cloud your judgement. Try stretching and breathing to help calm down. If that doesn't work do some push ups until you cant anymore. If you want some more advice feel free to send me a p.m. I'm no expert, but I definately understand what it's like to go through that sort of thing and am more than glad to help someone out and share my insight. Be safe and do do anything silly