Stuck in apartment, baby needs to poop

How do I get my child to poop? She’s 4 months old and off her pooping schedule and is VERY angry with it and keeps screaming and straining and her tummy is hard.

We’ve had this problem before but it was the formula but this time its not for sure.

I breastfeed 80% of the time and 20% formula.

Pediatrician says to try what motherly instinct says might help and if its not better in 2 days we’ll take her in.

Tmi, but i also am slightly constipated. Is there anything I can eat that will help both of us?

Otherwise what can I do to help her while we’re stuck in the apartment?