Impala, I think I might understand how you feel. I am going through a similar situation, and for me the "best" way to lose a friend is so that all is clear and there is no doubt that you could ever be friends. I tend to get too attached to people and if I don't know it is all over for sure, I also start thinking of those 'what if's'.
Although everybody else advices you to forget her, I don't know, maybe confronting her for the last time would actually help. Maybe you need to know just one thing for sure: that the friendship is ending for personality reasons and not for reasons that can be fixed. That is closure.
(Of course, it is possible that things can be fixed, which would be excellent)

I hope all the best to you, which ever way you get through it!