We found that when our newborn was that age and kept crying after we thought we tried everything, he was actually hungry again already. They change the amount they need pretty quickly, and also go through clusterfeeding, which is exhausting! It took us a while to figure that out. Newborns have no schedules, no so-called windows. They have needs and can only communicate by crying. It helps to think about how they were basically ripped from the perfect comfy home where they had no hunger or never felt cold and then suddenly it was gone. Being a baby is very difficult! I'm glad we don't have memories from being that young because honestly they would suck. Being hungry or cold or your clothes poking you in a weird way and not being able to communicate what is exactly wrong and unable to do anything about it yourself.