Baby won't poop

Randee • 21, FTM & single mom, to the most beautiful baby girl 🎀👑💕
It's been about 4 days since baby girl had a poopy diaper. Her tummy "gurgles" a lot & she's very fussy at times. Dr wasn't too concerned Monday but I'm getting worried now. I know she's hurting but I don't know what to do to help her. She's a week old & she's breastfed