The last line is what was throwing me off. Anyways, just open up and be honest. Ask her why things have changed all of a sudden. Why the change in tone in conversation. She could be interested in someone else or maybe simply having second thoughts. Maybe she is pulling back and reeling back as well? I think when a girl says "I'm a mess" that its a subtle way of trying to ward a guy off, like maybe she's not ready to give herself to someone else just yet.