Newborn vomiting yellow

Hi, my baby is 12 days old, in the hospital he wasn’t latching, so for the two days we were there, we gave him formula, when we got home I started pumping and had a good supply, so for a little bit we only gave him my breast milk through a bottle and then my supply went down very quickly, so for the last three days we have had to give him formula again, because I’m not producing enough, we give him the same formula that the hospital gave us and for these three days he has been vomiting something yellow once a day and it’s not spit up, usually happens in between feedings and it’s more than usual spit up, should we change the formula?