Help me GC?

[o2bame]

Hey all. My good friend who was close to me like a sister just recently crossed as a Delta. I am extremely happy for her however, and i cant help but feel like she is dogging me for her sorority. Now i know that its hard for someone like me on the outside looking in to understand but maybe you all can help me.
Well first I havent heard from my friend in about 4 months while she was in school. I knew that she might be in the process of pledging so i didnt sweat it i just supported her. However, my friend didnt even call me to tell me about her pro-show or that she crossed. I had to hear from another person from her school. Until this day my girl has not called me, emailed me or contact me at all. I am pretty ticked off and it makes me feel like she's just cancelling our friendship. Am I being petty and selfish? Should i be more understanding and realize that things will just have to be this way? Or is my friend the one that is tripping. I plan on calling her this weekend but i dont want to say anything hurtful especially if its not her fault. But I can help but feel like im being played. Talk to me GC....