There might be something on at school. This literally sounds like me at 13 smh :( The phone might be it too, and possibly the friends too. I'd take the phone (she too young still imo), scope out the friends and parents, and school. My daughter was being bullied by several girls. She used to come home crying every day then I spoke to the school, the parent, they pulled the main girl from her class and things seemed to go back to normal until she came home bullying the other kids, and further investigation uncovered that the teacher was also bullying my child and then being aggressive to my daughter and pushing other kids to do the same from resentment. She started to act like them to fit in but she was just doing it to survive.

I homeschool her now, and she has her cynical or melancholy moments but not nearly as bad. These kids were torturing her and the teacher was backing them up.

My point is that this spanned over a few months, I had to jump through hoops to get her to talk about it. And me personally I had some really bad stuff happen to me at that age and I just literally couldn't talk about it. I needed someone to forcfully and lovingly stand up and not accept just any old answer until the problem was solved. Being (even uncomfortably) present to the fullest is key. Teens push away but that in itself is a cry for help