Feeling So Guilty, Stressed Mom?

After fighting traffic for 50 minutes and rushing to pick kids up from school. I was behind some very slow moving drivers, disabled trucks, school buses, etc. I was very impatient. The last slow moving car had to been going 20 miles an hour & was the car in front of me in the school car rider line. This woman had a younger child in car who she allowed to play in car while we waited, hang out window, jump up & down in car. Anyway she held up the line when we got our kids because she had an issue with strapping her hyper kid back in. I was too impatient to travel behind her again so I passed her on a 2 lane hwy and sped my way home. This woman followed me to my home, did not get out of her car but slowed down. I was upset she did this, but I feel so guilty about speeding with my kids in the car and them asking me why I was upset. I know I overreacted due to SEVERE PMS, my mood has been jacked up all week. I am now concerned that I have to see this woman again at the school and if she called police or will alert school. I have learned my lesson but the guilt is so overwhelming now, I am also overworked, stressed, family issues, debt issues and I think I let it overtake me today. Are there any other stressed out working Mom's who can offer any kind advice?