Feel horrible:( help!

Ladies my older ds is 2.5yrs old. Always been a good lad, has his days but overall good. It is just now he wont listen esp in an emergency recall-long story shot we live right next to highway and he broke out of my hand and ran right to road and would not even look back when i was screaming his name. My brother ran like the wind to catch him. I was so scared i got him back and tapped his butt (not that he felt is his cloth dipes are cushy) but it scared him and he started screaming but i didnt know what to do :( i feel so bad for tapping his butt we never do that but it was so serious i wanted him to understand road very dangerous and mommys emergency recall. Can you help me ladies,? I feel like a bad mom :( i lost my cool and marbles i was so scared! How do you ladies discipline your lo's and get them to understand emergency recall and not run away from mommy? I just feel lately he hasnt been listening at all and acting out alot somedays I cry i want to do the best attachment parenting approach but i really need some help and suggestions.