My best friend is moving to australia and im so upset because i don't think i will ever see her again.?

My best friend is moving to australia and im so upset because i don't think i will ever see her again. She is leaving in august which is 2 months away. what shall i do about it? should i be happy for her and move on or just be sad and wait till the day comes. I cry all the time because she is my bestest friend in the world and i don't want to see her leave. it is upsetting because everybody always talks about it.