Hi... well I think you both are a little immature, and that's fine.. But when you know you are getting hurt then its time to think about yourself, and there's nothing selfish in that (in my opinion).
What I think is that this girl will always be this way, I mean fluctuating. Its okay to be friends but I don't see any future. And I am saying this because I am very much like this girl, (and not proud of it).
I hope now you know what to do..
Take care..