Welcome to the board!
Yup, my daughter is the exact same way. In fact, I just had a meeting at the school. When I informed them of her diagnosis (diagnosis) it was like they did not believe me. "But she is so sweet!" Uh-huh. Come be a fly on my wall sometime, I told them.
They lash out to whom they feel safest with. As Heather said, the love from us is unconditional, and they know it. Which is actually a sign of a GOOD parent, not a bad one.
Stick with us. We'll help you through this.