Help, Why's she acting like this?

My girlfriend broke up with me about 2 weeks ago because she is going overseas in about a month and she said the relationship was putting too much pressure on her and she wanted to be just friends. Anyway, since then she hasn’t been talking to me, she doesn’t talk to me on msn anymore and I have to start the conversation with her. Whenever I’m around her in person shes all sketchy and keeps her distance. She also never looks me in the eyes anymore unless I talk to her. Its like she doesnt want to be around me anymore but I don’t know why because I was good friends with her before the relationship and now she acts like nothing ever happened between us. I mean she will still speak to me but its like I’m a stranger. I was thinking this could just be her way of getting over me before she goes away but she already told my mate that she had lost feelings for me and im now starting to think she hates me and I don’t understand why. She could be weird because she knows I still like her and doesn’t want to lead me on or something but I don’t know. Its really hard trying to get over the relationship and trying to be friends with her at the same time but its starting to confuse me and I don’t want to lose her as a friend. Its hard to talk to her because I feel like she doesn’t really want to speak to me. My mates tried to talk to her about why shes doing this and she just gets angry at him because she doesn’t like talking about the subject of me. Shes going away in a month so I guess id get over it then but its really confusing me at the moment and I guess I don’t like leaving things left undone and it worries me that she could come back from being away and still be the same. Can anyone help me figure out while shes acting like this? any help will be appreciated