I need my girlfriend back...?

I really need help on this, I dont know what to do. Before you criticize me on being stupid for what I did, I already know that I was. Its a funny story how it began. It was 4th grade and this girl and I had a crush on each other, so we "went out" then. I'm kind of shy. So we "dated" through elementary school. I had to move to a different town for a year, my first year of middle school. Then I eventually moved back to the city where all my friends were the next year. My girlfriend and I didnt keep in touch throughout that time period, so I kind of became unattached with her, but I was still in love with her. When 7th grade started I was shy around her and her friends so I hung out with all the guys I knew instead of her. She broke up with me for not spending enough time with her and I hate myself for it. It's been practically 3 years since and my Freshman year of high school is nearly finished and she's dating one of my best friends. We never talk anymore, and I want to get her back and be around her. What do I do...I cant forgive myself.