This happened to my DD at a similar age, she was taking in plenty of foremilk but not enough hind milk, I can't remember the exact reason why it makes their poo green and frothy but it's something to do with the fat content? I made sure I double fed from the same boob and they returned to normal quite quickly. My DD was a bit of a snacker so it happened a fair amount.
Ebf 12 week old. No excessive vomiting or excessive fussiness apart from the three hours before bed when she's a terror. But a lot of her nappies look like this? Is this a typical nappy for a dairy intolerant child? As I read green and mucousy are signs of dairy allergy