I have really bad issues of codependency. When I perceive someone is pushing me away, I cling tighter and tighter to get them to love me and stay.
My big sister always tells me "turn down the volume". Basically take step back, stop fighting so hard and so desperately, and let the person be.
She also says: "it really isn't always about you. People are essentially self/centered. Most of what they are thinking or feeling has nothing to do with you."
I have no idea what might be truly happening in his or her life and head. I may well be making problems (if one even exists) between us a lot worse. I need to go my own way and take care of myself. Maybe check back in with that person in a awhile (like weeks) in a light, not super serious way. Occasionally someone will get back with me first. Yes friends have walked away and I have walked away from friends. It happens. It hurts. But agonizing and trying to force a relationship to continue that has run it's course, that's even worse.
My best advice would be let her go, focus on getting you better and healthier, and maybe making a new friend or two.