It is inconsiderate of her, regardless of what happened to mess up the plans, she should keep you better informed. Things can change unexpectedly but if you let folk know your intent has been foiled and why, then they are more understanding.
And it's frustrating for you as you changed your plans just to see everything go awry ensuring you made the wrong decisions. But life is less stressful if you take a deep breath, perhaps even count to ten, or ten million if necessary, and tell yourself to chill out. Ultimately getting riled only harms you. Sorts nothing.
Do as anne suggested, wait what you consider long enough, and then tell her the kids are restless and so you are off with them. It's fair enough, she needs to be at least as understanding as yourself about the situation.