How to get over this stupid friend?

We used to be best friends since grade 10. Now we're in grade 12, and we graduate in two months. My friend is being very stupid and going through a phase. This has been going on since September. I call her and we try to hang out, but she always cancels on me or ignores me. In the hallways at school, I used to hang out w/ her in between classes. Now she just waves and sometimes completely ignore me. A couple of days ago, I saw her talking to her boyfriend. Not having seen her in a while, I thought I'd go up and talk to her. So I said hi but she didn't seem to notice me standing there. Her boyfriewnd finally pointed me out to her, and she just said ';can you...sort of...leave us alone? I need to talk to him.'; So I left without even saying a word to them. Today we were supposed to hang out. So I called her house twice, no answer. Texted her, no reply. Phoned her house again. Brother answered. Said he'd pass message on but still no reply. I'm getting very frustrated with this girl. I know she's not worth my time if she's treating me like this, but you have to understand that she once helped me through a difficult time in my life which I'm still going through, and I feel like I have absolutely no one else to talk to. The thing is, she knows I'm in pain. Yes, her schedule is busy, but she still makes plenty of time for her boyfriend and other friends. After I graduate I will try one last time to stay in touch with her, and if she still wants to play this little ';game'; with me, then fine. But I'm having a hard time getting over her and I just said why above. So, how do I get over her?How to get over this stupid friend?
Why don't you just send this message to her email?