After seeing Joy be her pretty normal self today I've decided that possibly what was going on last week was something like her waiting for the results of a test--like a biopsy. You know--the kind of thing that the docs can't tell you anything about until they get the results and it's either going to be okay--or be really bad news.
It might have been for herself--or for her daughter. We often worry more about our loved ones than we do for ourselves in those situations.
She seems to have come through whatever it was okay.
(Disclaimer--The above is my supposition based on nothing more than how I perceived her to be feeling/acting last week. No actual facts were used in forming this personal opinion.)