C'mon now you should've known what to do from the start. This girl is too immature in every sense of the word to survive a long term relationship with you. You have other options -- aren't they better than her?
I can expect this girl to freak out over the smallest things. If a couple of tough weeks at work can set her off that she quits on her relationship what's going to happen when something truly important comes up?
I look at how people react to small things to gauge how they react to important things. Nothing bothers me unless it's truly important; I let the trivial things slide. If a girl is always using the trivial things (the stuff that happens every week) ruin her day, she's either a drama queen or immature.
She may not have done anything wrong to you, but as the logical player asked (though I'm sure he has different conclusions): why do you have [this girl] as your girlfriend?
Finally I think you need to learn how to be an ******* more. It works great for situations where you shouldn't be taking anybody seriously, like when she blames you for the actions of your friends. Jesus Christ....
Run. Run far away.