ITHurts, I didn't get to respond earlier but to me it sounds like your ex-wife was talking to a friend about her plans with you and someone told her to slow down and not appear too eager. It seems like someone else influenced her to cancel. Or maybe she really wasn't feeling well and didn't have a chance to look as beautiful as she wanted to be in order to impress you.
Have you heard from her again? If you told her you'll be working all week then my guess is you'll hear from her at the end-of-the-week.