This is so familiar. Our family had a similar experience this summer. My wife took our 9 month old to a pool party (sounded like a good idea at the time...), and the next day he was running at both ends. Then my wife got it, then our 3 year old, then me. As noble as our efforts were to stop it from spreading, it was no use. We almost called the in-laws, but managed (barely) on our own.

I had similar thoughts as you expressed when this happened. We keep stocks of food and medicine on hand, but this reminds me to be more diligent about not getting behind.