1 month old is constipated

So i breastfed my baby til she was about 3 weeks old and everything was fine got her on the blue can formula Similac advance and constipated her badly

It was so sad. I couldnt handle seeing her in so much pain so we switched to the Similac sensitive and it worked for her.

I messed up before switching her i went to wic and they had given me the blue cans so i used them because i didnt want them to go to waste so now that im done with them she is back on the orange can and is sleeping and acting way better but not pooping again.

I switched her back Wednesday and she pooped thursday but hasnt since.

Is there something i can give her to help her poop? I can tell shes constipated just wanna know what i can give her because shes only a month.