Switching formula

I breast and formula feed. Baby was having huge burps during formula feeding and about 20 minutes after making him super fussy. I try’d the switch to soy to see if that would help, been on it for a week and he’s pooping less (green when he does) and I feel like he’s even more fussy, takes a long time to settle him. Did this happen to anyone else? Think I’ll continue breast feeding and go back to his regular formula.