Shocked when I knew some bad news

Last week, I heard a unexpectedly bad news that my junior at my last university was dead. Actually she had died since the end of last year but i don't know it at all. I know the news because I accidentally saw her web board on website "hotmail" and what I saw is a lot of memorial speech from her friends to her. I felt very shocked as if I was hit by something hard and then I was speechless. Although we are not very close, she respects me like a brother and I always feel she's my sister but from now on I can't talk to her any longer, even say "good bye". Only one thing i say to her is "Rest in Peace", the best thing I can do now. Due to her death, I must turn to anyone I love to take care of them more. No one knows their own future. Her death is like a warning that makes me aware humans have no much time, so we should do anything good to others and ourselves as much as possible.