J.W.
I am the proud owner of 4 kids, 3 of whom are potty trained (Harry is just 2, so he's got some time). the regression is probably a combination of things. Going away for a week is a HUGE disruption, and little kids are creatures of habit. She just got into the swing of things at Gramma's house just in time to go back home again. And because you probably don't see your nephew much, and your mom doesn't see your little ones much, the babies probably did get a lot of attention. What I would do when these baby regressions reared their annoying little heads is indulge them to the point of annoyance on my kids part. So fine, you want diapers. Well, babies wear diapers, and babies can't play with hot wheels or Barbie, or what ever big kid toy they love to pieces at the moment. Fine, you want a bottle? Well, BABIES don't get cow milk, they get mommy milk or formula (formula fixes their wagon REAL quick, blech). it suddenly makes being a BIG KID so much more desirable...