Formula help!

Shannon • Married💙💍 Mother of 3 beautiful girls💜💜💜

Mommas, I need help finding a better formula for my little girl. She is almost 9 months in a few weeks. She gets supper constipated & her pedtrician recommends that I give her miralax every day to help, but I do not like the idea. She also has a sensitive tummy and spits up quite a bit. I have tried Similac pro sensitive, Similac soy, and Similac alimentium. Please if you have any suggestions on what type of formula to use I would really appreciate it!! Also we have tried puree prunes and it doesn't seem to work well.