Hello everyone! The baby is almost a month old and we're doing mixed f…

Hello everyone! The baby is almost a month old and we're doing mixed feeding. We give him/her warm water in small amounts, he/she hasn't pooped for two days, he/she cries and fusses, yesterday there was pasty poop. We'll see the doctor only in two days. Is it normal? What could be causing this? He/She used to poop once a day consistently before.