She will have so much fun at "pre-cool"! She'll make new friends, explore her world, develop her independence! It's much more difficult for you, as I'm sure you know.
Make a conscious choice to live in the present. Be present in every moment of your life, particularly those with the kiddos. If you are organized and plan carefully, you can schedule your errands and chores as well as specific times to be focused on the child(ren).
And ask for help! That's my biggest challenge, not trying to do it all by myself. I'm so bad about that.
Hope that helps! It will take a while to adjust, but you'll do great!