I can't get over losing my best friend?

I was best friends with this girl for years, we became best friends when we found out the guys we were dating, were actually brothers. So we grew a strong bond because we had something huge in common. The thing is, they broke our hearts and she got a different boyfriend. I never wanted one. She started spending all of her time with him. I had to beg her to hang out with me and when she did, she'd spend the ENTIRE time talking on the phone with him-And she'd only hang with me for less than an hr. So after a while we just stopped hanging out. Months went by and I haven't heard from her, so I asked if she'd like to go see a movie with me and she agreed, but on the day of she bailed, saying she thought her bf was working that day but turns out he wasnt so she wanted to spend it with him. I wouldve been okay except she told me this hours after she was already supposed to be at my house. So I saw the movie myself. Later we got into this HUGE argument. I feel she's changed. I don't see her at ALL. And we've been out of high school for years so there's no way I can see her, because in High school when you shared the same class you never had a choice to see them or not. Anyway, so I sent her a few texts saying I miss her, and she'd either ignore me, or have her friends talk bad about me on my own facebook wall. Saying I'm an empty headed b*tch and I'm dumb, bla bla bla...Funny thing is I got accepted into a prestigious college so obviously they're wrong to think I'm beneath them by any means. But lately it feels like I've been missing her so much, except every time i try to talk to her she ignores me. I just bought a house with my fiance and everything is going good in my life, so why can't I just forget about her? Why does it feel like she doesn't give a damn about me? Help me please, I can't get over this, and I haven't seen her since August of 2010...