i'm losing it!

i have to tell you something : i'm a very emotional girl. when i was in elementary school, i had a fight with one of my friends. because i was so angry with her ******* talk, i threw my cell phone at her. unfortunately, it didn't hit her. and then one time i was angry at my maids because they seem like they didn't care about me, i threw every pillow on the sofa to every corner of my house. and the worst part was when i'm mad at my mom. i hung up at her phone calls and then i slam every door that i went through. it makes me look like i'm a spoiled brat, doesn't it?
in 6th grade, i started to realize that i had to control my emotions. so, i was beggining to look for stuff that could lessen the anger in me. thought about happy things, didn't work, took a deep breath, a little bit, and then i found the perfect solution, i created a fist whenever i was angry and imagined that i was punching a bag of sands. and it seriously worked!
now, i'm still using that method. but recently, i started to lose it. whenever i'm angry, i can't remember about the fist. i only think about punching that person in the face or yell at the person and left him/her speechless. i really have to control my self, or i might end up in serious trouble.
just a few hours ago, i was at school. the boys in my class teased me and, like you guess, i started to lose control of my emotions again. i wanna just hit them and yell at them until someone locked me in a room!!
hhhh.. why am i losing it?! it's fine just a few months ago. and now i almost lose it all. what's wrong with me? what did i do wrong? can someone help????!!!