Formula question??

I had my baby initially on similac pro active . She was pooping once a day and it seemed she was in pain before going so at the pediatricians advice we changed her to similac pro advance sensitive which didn't change much the situation. Today we changed her on sinilac alimentum and she seems even worse. Any advice or thought? I am trying to guess what the issue is, I don't know which other formulas to try. Did any of you go through this and do you have any suggestions?

Thank you