Talk to Pediatrician on My 2 Month Old Son Is Not Passing Stools

my son is 2 month old. he was on combination feeding for first 40 days. formula milk and mother feed both. then after 40 days i stopped giving him formula milk completely and started exclusive breastfeeding. since then he has stopped passing stools. he used to poo normally once or twice a day when he was on mixed feeding, but now he doesn't poo at all. i used a suppository and he passed stool which was a little bit hard then again 10 days passed and he didn't poo. so i used 2nd suppository and this time the stool was watery and not hard at all. i wonder what has happened to him? what should I do now? he is gassy and farts a lot too but then he gets better quickly and doesn't seem that he is colic. why is he not passing stools normally?