I know exactly what you mean. I get so impatient even sitting at a red light. I yell at people constantly when I'm driving... it is just horrid.
How are you relieving stress? Do you workout? Maybe a hot bath with some calming tea? Make sure to take time for yourself.... You ARE a better mom, even if you will yell at them a bit more for the next month or so, you are a great mom to decide to be sober. I envy you!!!!