Constipation

Hey y’all. Question for moms who formula feed and have dealt with/are dealing with constipation. My girl was super gassy on Similac Sensitive so we switched to Enfamil to see if it would help. Instead it got her super constipated (screaming when pooping and minor blood in stool when straining). Our doctor recommended prune juice so we did that and switched back to Similac Sensitive. It seemed to do the trick for a couple weeks. Now all of a sudden she’s starting to get constipated on Similac. Any formula recommendations?

We already do tummy massages, warm bathes, gripe water and bicycle legs to help.