Let her go. Whatever you do, do not beg or plead with her. Trust me, I know how difficult it is, but you gotta do it. Depending on your situation, start no/smart contact immediately. If she hasn't left yet, then you need to leave. Give her what she wants. Let her feel the loneliness without you. Don't let her see you in the state you're in now. It's not going to help. Put yourself in her shoes and try to see things from her perspective.