My Best Friend Left Me.

We had been best friends since we were in 5th grade (I'm a ninth grader now). She was so kind and we made projects. I was so happy with her. Until we had a huge fight in 6th grade. we had a fight for almost a year. In 7th grade, we were in the same class, and we slowly became best friends again. We trusted each other and loved each other sincerely. We did everything together and we shared everything, till a huge fight in 9th grade, November 2011. I did something that hurtful to her. She keeps apologizes, but I was so dumb that I didn't realize that she was my only true friend. January 2012, I apologized to her and asked her to be my best friend again, and she sincerely forgives me... I felt so lucky that day... But it didn't last long. Today, she said to me that we can't be best friends anymore (just friends). I was so surprised that I cried loudly and asked her why. She said that I've changed, and she said that my bad behavior hurt her really much in the past and she's trying to get over it. I know I deserve it, I realized I'm such a bad friend to her, I'm a bad person... But I'll always need a best friend like her, who always accepts me just the way I am and tells me my bad behaviors. I missed her so badly. All I want now is to have her as my best friend again... She gave me so much and I don't want to lose such a great best friend. She's my everything (besides God and my family). What should I do to get her back? :'(