My 4-week-old spent his first three weeks as a good eater and a good sleeper. Then his poop started turning green, and he got very gassy. Googling around, the two explanations I can find are oversupply and food allergy.
His poops are green, loose, and frequent, but not frothy
He is very gassy
He is gaining weight much faster than most babies (1.5-2 oz per day)
He's very fussy, and can't seem to sleep well during the day
But I'm never engorged or leaking, even when he sleeps the occasional 4 hour stretch at night.
I don't know if the fast weight gain is a symptom. My first baby also gained weight quickly, but never had green poop.
Likewise, last time I almost never got engorged. It took a full 24 hours to start leaking when he was 8 months old (and the size of a 1-year-old) and still exclusively breastfeeding.
So why is my baby fussy and pooping green? The crying is driving us all crazy.