It's hard to give precise advice without knowing what the uncontrollable circumstances are. Though you're discretion does give some subtle clues.
I would back off and give her plenty of space. What ever it was has obviously caused some post-traumatic stress, which happens in life sometimes. By continuing to prod her, you'll push her away from you more, which sounds like the last thing you want.
Plan on not calling or contacting her for at least a week. Plan to go and do somethings you used to do before you were exclusive with her. Go and do distracting things that help you think about what good things you have in your life besides her. Take this as a "loving yourself" moment. Especially since it sounds like whatever has happened, has affected you to. Don't neglect yourself in an effort not to lose her.
By focusing on yourself, giving her some space and bringing more happy thoughts into your life at the moment, you will attract more happiness. Which will probably attract your girl back. Plus, it might give you some time to mull over what ways you can help cheer up your girl and reconnect with her.
Take some time to consider that whatever has happened, may have changed your relationship in her mind and she might not be able to get past it. Remember that she is not the only one out there for you and that you won't melt away if you two don't stay together. I know it doesn't seem like a great thought at the moment, but considering that you seem like you love her, you might need to let it go for her sake. By preparing your mind for the possibility now, if it comes down to it later, it won't be so hard to process.
After a week, if she hasn't contacted you in any intimate way, then you can try giving her a call or sending her a message. Don't be pushy or urgent. Do it when you're calm, happy and just contact her to see how she's doing. She'll be able to tell if you're just trying to get back with her and it won't work.
Well, I hope this long winded answer helps. Good luck