Constipation?

T

My 4 month old has been having trouble pooping lately. She’s straining, crying in pain, and her poops are coming out solid and as big as a quarter :( poor girl. She’s been on Nutramigen for a few months now because she was colic and gassy. It seemed to have worked fine until a couple of weeks ago. She’s been eating solids for two weeks now. Sweet potato and avocado so far. Maybe I need to switch formulas again? She has an appointment next week