Hi. All that back and forth is confusing and hurtful and I am sorry you are experiencing it.
How do you deal with the constant jumping back and forth ?
I would start by looking at what you want. Do you want to get back together with her? If so what are you hoping for?
I think you should take a look at the way your relationship was, what the deal breakers were for you, if you think you can get back into a relationship with her and have things be different or if it will be more of the same.
I know I am not directly answering your question here. I guess what I am saying is that instead of figuring out what she wants and what her actions mean, that you should take a realistic look at you, what you want and what it means that you are willing to get back with her. Work on that here and you will know what to do with all the back and forth because you will know what you want.