Baby poop question.

Justia
My 4 week old baby is pooping after almost every feed in small amounts. But her poop is greenish with mostly seeds. It also looks a bit slimy which has me a bit worried. But she has been congested for a few days... could that cause mucous in her poop or could it be something else? Is it normal ? 
She also sometimes screams or grunts when she's pooping. Why is that? 
Can't believe my baby's poop got me so worried 😩