What should I do about my friend?(See Details)

I have been concerned about this all year, and didn’t think until now to ask Fluther.
My friend is a freshman like me. She is on the field hockey team, which has practice everyday there isn’t a game. After that, she still has to go home and do 3 and a half hours of homework because she is in all honors classes. She is also a flute player and has lessons on Wendsdays and Tuesdays and Thursdays she has rehearsal for her big high class orchestra. For that, she goes to competitions on weekends at least once a month, sometimes more. She is also trying to do all 35 of her community service hours this year too. She started off the year pretty good, but now I can see her burning out.
She is obviously doing too much, but everytime I tell her that, she claims to be fine. But now she isn’t eating as much as she should, sleeping 5 hours a day, and she just doesn’t look or act like she used to.
What should I do to help her? I’m her best friend, so I would feel bad if something happened and want to help her. She isn’t cooperating well here.