Thanks for the loving responses, mamas!
About having a mother's helper for some time off, the embarassing thing is that she just started a five-day-a-week preschool. She LOVES it, but it's sooooo much more time away from home then I was imagining for her. (They're short days, but still.) And for various reasons it's our only preschool option.
Anyway, I totally thought that a bit of time apart would fix all our problems, even though there is still a good seven hours of continuous contact every day, not even counting the long mornings before school starts.

Some of your suggestions have really helped me; choosing / seeking out activities that I
can stand. Tonight we made stamps out of potatos.

Now if I could just stand up to the inevitable guilt tripping- I play with her for an hour, and then say "Now Mommy's gonna take a break", and all of a sudden she bursts out with "I feel like you don't play with meeee!"
