My friendship breakdown is hurting me much more than I let on to others.?

It's possible something really bad happened in her life and it made her upset and it caused her to distance herself from you and others. This same thing could have also made her more easily upset by somethings then she normally would be. I know I get that way when I have a lot of family drama. Problems in her life also could make her more jealous of you. I have a friend whose like this and it's usually because of problems in his life rather then things I've done. If you want to stay friends talk to her about it and suggest she see counseling if it could help the situation. If it's healthier for you that the friendship ends though slowly distance yourself from her. She also could be the kind of girl who gets into a lot of silly girl drama and that's tough on a friendship. It might be hard but sometimes distancing yourself could be what's best for you. Hope this helps :)