Quoting ANS: Maybe I'm exaggerating my own importance. It may not be about me at all. But if it isn't, then why won't she tell me what's wrong?
Maybe she doesn't know! If so, perhaps time to back off a bit, give her the space and time needed to figure it out, and dont start that same dance you were describing earlier: distance, pursue, three steps forward, two steps back.
In the meantime, dont give her any reason to start it on her own!