DON'T TAKE THINGS PERSONALLY!!! Agreement 2!
More than likely she just was stressed for an unrelated reason. Just let her know you're there to help with whatever you can, and remember not to take anything personally. That would cause more stress because if it's not you then your undermining the significance of what might be actually stressing her out. Clarify what's going and like I said offer what you can to help her de-stress.
If you don't take things personally you won't mirror her stress either which could also cause issues. Keep your head about you and everything will be fine.
Ted, how do I explain this to you. Last night, I ate the best cake of my life. Do you think I'm gonna let that cake out of my life? Hell no. I'm gonna find out what bakery made that cake and I'm gonna get some more cake.