So, you didn't use an enforceable statement. You rescued your child from a natural consequence. You used fighting words instead of thinking words. What now?
Go take a nap. It sound like you need one. (Me too!) But most of all know that God made children incredibly resilient. A few failures here and there won't spell disaster. Receive God's Grace - His unconditional love for you and your child. Wallow in forgiveness instead of self pity and when you are well rested again, listen to a Love and Logic CD or talk through some of the situations that flustered you with a Love and Logic buddy who might help you develop some ideas for how to handle the same situations differently.
Tomorrow is another day. It's okay.