3 week old not pooping as much

So we switched formulas on Wednesday to help with gassy baby, she pooped fine until Yesterday...after about noon she didn’t poop again until like 3 am when I stuck a thermometer up her butt lol now she’s only pooped one other time since then. She normally would be pooping like every other diaper change. Is this bc of the formula switch? Should I be worried? FTM here so I’m always worried lol