Solid poops at 7 weeks old

Br

My daughter is 7 weeks old, she will be 2 months August 9. I took her to the doctor yesterday due to her acid reflux and her poops. She’s been pooping solid poops and by solid, I mean pebbles/rocks. She hasn’t had a mushy, normal poop in at least 3 days. They just stuck a thermometer up her butt and said “she’s about to poop, so you’ll need to let her lay there and fill it up” we waited 10 mins for her to poop and she never did, she never pooped until the next day. Today, I did the thermometer up her butt while she’s pushing it out, to see if maybe it would help, it didn’t. I felt so sad watching her push her poop out. Does anyone recommend anything for that? They switched her formula (they said that could be the reason, along with reflux) but they said to call in a week if it hasn’t gotten better and I don’t want her going another week with pushing these hard rock poops out and her just hurt her insides bc I know it’s gotta hurt her little butt.