I fell i have lost this girl and will never see her again what should i do?

Me and this girl have alot of history we have been friends since i first joined high school in year 8 we decided to have a relationship as a joke as we were both young. the realationship shortyly ended as it was just abit of fun but she seemed to take it seriously. this had an effect on our friendship for a while. towardes the end of year 9 we had become good friends again and begun to hand out more. when it came to christmas in year 10 we had realy started to like each other and people had tryed to set us up but it just hadnt worked as we were both too shy(mainly me) this girl from leeds who i had met at a party began to take an interest in me and so i went out with her for a while. i realised that it had started to upset her and so i broke it off and had finally plucked up the courage to ask her out when i found out that she was going out with this boy that i hated with a vegence. i had no idea she was even into him which shocked me even more as we were friends and told each other virtually everything.At this point i was so angry i couldnt control myself so i sent her a text saying how much i hated her and that i never wanted to see her again. she rang her boyfriend aparantly crying her eyes out and saying how much she hated me. he then sent me abusiuve messages and threats as he had been doing before but it never bothered me until then.. he then took at step furtehr and threw a snowball at my window this was the last straw as i was so besieged by rage i ran out out after him threw him to the floor and punched again and again until i realised what i had done. nothing more came of that night but i felt so guilty as this boy is from a troubled famill and is very easily influenced. as i came back to school i learned that she had dumped him which was strange. we didnt speak for a year and when we finally did it was at prom were we spent quite alot of time talking about the past the question of my love for her never sprang up but i wish with all my heart that i plucked up the courage to tell her how i feel. we had become extremely close again just recently and i had planned to take her out for a meal somewhere as it was the end of year 11 and everyone was in tears. she is going to colledge to do art and dessign and i plan to stay on at sisxth form and do econimics english and history and maths. i recentlt found out she had a new boyfriend one who is 5 years older than her she is 16 like meand he is 21 it breaks my heart as i cannot comfront him about it because is a massive chav and renown for being vioent. i do not know what she sees in him but i realy want to be with her i am unsure wheather or not she feels the same way but i would like to try WHAT SHOULDI DOO!! i do not want to staright up tell her my feelingd and that would cause to much coruption and confronation and i want to slowly get back into her life> what do i do???