What do or should I do?

well, what you should do, is have a talk with your friend, and then you should have a talk with an adult, preferably her parents, then from there, her parents should be able to help her and you should too. she may be down, but you have to help her get "back up" again, you're her friend, have fun, and let her know that you will always be there for her. hope i helped a little.