Aw, I'm sorry.
I'm home with DD2 as well, while DH and DD1 are at church, because she's been such a behavior issue in the past there that I've essentially given up for now. (Yes, I know this is not a great solution, but there you go.)
I don't think you can blame yourself for what you are or are not doing with her. Every DC is a different person, and they don't come with instruction manuals. It would be so much easier if they did, right? "In case of tantrum, say this phrase and tantrum will instantly be transformed to sunny mood."
I found 3-5 to be INCREDIBLY difficult with DD1. So much so that I didn't think we'd both survive. She became somewhat easier at 6. We've had ups and downs since then, and I'm pretty sure if we both survive her teenage years it will be nothing short of a miracle.
On the other hand, 4 with DD2 has been the most charming, fabulous age. So I'm 100% sure it's a personality thing and not some failing in me as a parent. And I'm 100% sure the same holds true for you.
Not that that makes it any easier to deal with in the moment.
Sarah
Mommy to:
Carolyn, 10/04
Anna, 7/08
Matthew, 8/13