Hello ?? Is it normal for a child to poop once every two days and also…

Hello ?? Is it normal for a child to poop once every two days and also be constipated with redness and sometimes crying? The stool is dense but not hard. We're on exclusive breastfeeding (we eat NENNI with prebiotics 1). We're three months old today... At the beginning, when we switched to NENNI (and I was still giving Plantex), the stool was once a day... Now I think I'm having constipation again? How can this be? She drinks water at 300ml per day, she eats the mixture in one intake of 120ml.