I am a horrible mom!!

I was cuddling my daughter to sleep tonight (as normal) and she hit me, really hard in the eye, causing me to see white for a moment. A second after she did it I caught the palm of her hand with my teeth, I sort of bit her ... not at all hard. She opened her mouth like she was shocked and then she laughed and I said "only gentle touches to mama please" and we continued cuddling. Now I feel horrible!!! I don't even know why or how that happened!