think I've made a mistake

Sooo I'm a FTM & my son is one week. I've been having the worst butt cramps ever when trying to use the restroom. So yesterday I took a laxative BTW I am breastfeeding. Well today my baby has been pooping like crazy and its watery poop..... so do you think he's getting use to my breast milk or counseling the laxative be the reason...?