Terrible Twos Already?

That post about the kids being a lot of fun...ahem, I take that back. As of right now, Sadie has jumped up and down and cried pretty much continuously, with rare "listening" breaks for 67 minutes straight. It has been over 3 hours since she first showed signs of being ready for a nap and perhaps I put her off too long. She usually cries less than 15 seconds when I put her down! I've been back in there 3 times in the last 60 minutes to retrieve her blanket from the floor where it has been cast and to gently tell her "nighty, night, Nanna loves you, it's time for nap now." Only for it to start all over again....so, what's a Nanna (or mommy or daddy) to do???