I'm not just going to roll a "bail out" line for you as this seems to be the most common response in a Girl-Age thread, but you know, I'd just think for a while about what it is that you want to do. The problem really lies in the fact that she doesn't want to face her problems with you and that can be a pretty hard thing to come to terms with. I'm talking out of experience here. My girlfriend has a chronic illness called HMS, I'll spare you the details, but she suffers a lot because of it. It's a day by day thing and most of the time, you know the meds help her just fine, but it's really hard on her personally as well, because on the days the meds don't really help, she's in an aweful lot of pain all the time. Now when she was first diagnosed with HMS, I got all the same things, "going through a rough time" and as weeks passed by she kept on pushing me away even further and further. She became really passive agressive and she really tried to hit me where it hurts the most. And I myself was in a lot of doubts about everything.
So you know, one night I just sat down and I just thought a whole lot about the situation at hand. She had really pushed me to that point where I was really on the verge of saying, "f**k this, I've had enough of it". And it takes a rather long time before someone can push me that far, because I am pretty lenient, I had a rough time growing up and I know what it's like being the one who always ends up with the short end of the stick. But I can take in a whole lot because of it. But I sat down wondering if she really was worth all of the trouble. And I decided to give it one more shot, because I really did love her and because I knew, what was still deep down inside of her, all those great things that I liked about her, trapped behind a wall of anger that she built around herself. But I did give it shot, because I thought she was worth it. And we're 2 years later now and I haven't had a single regret in my mind about doing it. And sometimes it is really hard and conflict does emerge, but I've learned my ways to work around that, because her illness is something she'll have to live with for the rest of her life and I need to understand that if want to continue building a future with her. And despite the bad moments, the good makes up for it and it took a lot of time and patience, but right now she knows that she doesn't have to fight all this pain on her own because I'll be there right beside her when she needs me the most.
The circumstances aren't exactly the same, but if you doubt everything well, just ask yourself the question if she's worth it. That's something that only you can decide. Give her some time and maybe she'll come back to you and otherwise, in a week or so give it a shot to talk to her again. And you'll see how things work out. Are you really going to get out of it better by bailing out instead of having her tell you that she wants to end things? And maybe things won't even come that far. I really do think that it just starts with a simple notion of what is she worth to you? And if she is worth a lot, then start things slow, gradually build up the conversation, but try to avoid to push her in a corner, because that's when things might go sour really, really fast. I guess most people are probably going to say that this is bad advice but well it's just how I feel about these things.