Hard formed poops with a 4 week old

Chalie

My baby will be 4 weeks tomorrow. She has been pooping hard formed balls. I know this is a sign of constipation but could it be something else? We switched to formula a week ago and she seemed to adjust to it fine and now yesterday and today she’s had hard poop. Anyone experience this?

I will be calling her DR in the morning. Just looking for personal experience stories.