What do i do!! im so depressed now!?

OK, me and my 3 buddies, Mitch, Nate, and Joe went to Syracuse University this weekend to visit my friend and her roommate, Jess and Kayla. I really like Kayla, like alot. she doesnt really like me back, she does lead me on a ton though. Kayla does like Nate alot also. So, saturday night, Kayla and Nate swiped each others V cards. and im like depressed now because now i know shes gonna be attached to him for the rest of her life basically. I got really pissed and walked around at like 4 in the morning, and im pretty sure i broke my knuckle punching a stop sign. I wanna scream, i wanna cry, im sad, i just have no idea what to do because ive liked Kayla for about 3 years. and we would like cuddle and stuff, but she just ****** my best friend. Its extremely hard to forget about Kayla, ive tried, after i knew she was just leading me on, and found new girls for months, but something everytime just draws me back to Kayla, i feel like we were meant to be. Please help. i have no idea what to do. i feel like killing myself, im not dumb enough to kill myself, but this is just the worst feeling ever :((((