Suggest Medication For Diarrhea Or Constipation In An Infant While On Gerber Gentile Formula, And Similac Sensitive, Respectively

Hi :D My 1 month old godson seems to be having pottie/tummy issues... He started with Gerber Gentile formula and his movements were more like diarrhea and sometimes almost projectile... Doc switched him to Similac Sensitive and now he appears to be constipated and extremely gaseous, curd-like spitup and he s very uncomfortable... Can you recommend something to sooth till we speak to doc Monday? Thank you so much!