PLEASE I need help from teachers, counselors or parents of teens?

I have a 14 yr old daughter who is in her first year of hs. Yesterday some information surfaced that has me very upset. She told me last night that she purchased speed from a girl at school and the girl is suppose to bring it in to her today. Her sister told us that she told her that she also took speed at the football game Friday night. Her father and her go together, apperatenly she went into the bathroom with a friend and took it. She said that she did tell her sister this, but it was a lie. Imagine that. Well anyway, I found out she has been on MySpace and I took a look at her message history and seen a message in which she was asking someone for pills back on 10/18. Her words "I love pot and pills." When I contfronted her, she told me that she is just so depressed that she wants to be dead and she never took the pills, but wanted to.She has an appt this am for bloodwork. She is normally a good studentand I am afraid that she will be suspended. Should I tell the school?