I am afraid I will never see this girl again.?

I feel horrible about this.... Some Indonesian girl who likes me has been in my middle school and now she is in a different high school. I feel this way because I never got to tell her how I feel about her, and I feel good. But now I don't think I'll ever get to do so of telling her and I am afraid she will forget me and get over me. I can't access her face book and message her because of some attachment thing.And every time I read it I feel horrible inside. How do I cope with this?