How can I control my anger??

Im 15. I just get so mad sometimes. Between my grades(which im trying to p all my grades), getting teased on almost a daily basis, in love with a girl that has a boyfriend(who somehow found out i like her, and is pissed, and told me to leave her alone), my parent's meddling, i just want to frickin tear somebody apart. I get so pissed when I see my crush and her bf, and the worst part is that no matter how many girls ive dated, she's still in my mind! It's like whenever I see them together, my mind just goes insane. Picture "Two-Face" from Batman. Like a split personality. I am not exaggerating. I need help, because one of these days i feel like im going to snap(though i have enough control not to kill someone, but I can still whale their head off.)