HELP friend problem!?

After a schhol skiing trip my best friend has become quite popular and doesn't hang out with me and our other friends at break times. whenever we're walking around in the corridors she is always stopping and talking to people which I don't mind it's just that I don't know what to do when she does. I just stand there and go red in the face. What can I do to become a little more popular? I would hang out with my best friend at break but I wouldn't know what to say to all her new friends-the popular people and am scared of rejection. please help me.