Help with a depressed friend?

I currently have a friend, that is severely depressed, has ADD, ADHD, and is suecial. i am very, very, VERY stressed, and i need some help on what to do. she is very short tempered, too. she also made a "deal" with another one of my friends that she wouldnt do drugs, and the deal lasted until the end of the school year, and the school year is about to end and im SOOOO worried :'(. she is very stupid that way and it's very infuriating. she also has a therapist tht she sees every onece in a while, but not often enough. o and one day she said she took 4 ibuprophens... she said it was to help her sleep but...shes also on antidepressants,she fights with her parents a LOT. (theyre divorced) PLEASE HELP!! i cant go on much longer with this stress....