HP, in my opinion, there's nothing wrong with saying, "I'm sorry, this isn't a good time for me to talk. I have to get to the office early today. Could we talk ___(suggest a time that you can focus)." It's not only the time to process what she's saying, it's the time to actually listen, and if you don't have time to do that justice, then it's perfectly OK to suggest a different time. You just have to follow through and actually listen to her later.
