Things are never easy, and they were even worse when I was your age. Think of all the drama you are going through now as a right of passage, if you make it through then you will know a whole lot more about yourself. You're going into high school next year, and it's a big step. It was at the same age that I realized not everyone is as nice as they want you to think, especially your friends. Don't feel bad about hanging out with different people. Sometimes we need to get to know new people, and forget those who've wronged us.
As for your depressed friend, just be careful. If she is depressed enough to hurt herself, you need to tell an adult. I suggest you just sit down and have a good talk with her, try and be a shoulder. Don't ignore her. She may only want attention, but it's better to be concerned and with good intentions than to ignore her. Talking will most likely help both of you understand what's wrong; but don't force it on her.
As for your depressed friend, just be careful. If she is depressed enough to hurt herself, you need to tell an adult. I suggest you just sit down and have a good talk with her, try and be a shoulder. Don't ignore her. She may only want attention, but it's better to be concerned and with good intentions than to ignore her. Talking will most likely help both of you understand what's wrong; but don't force it on her.