Aw hirap yan, mama! Kaya ng lactose intolerance sa ganitong edad, pero ang dami naming kaibigan na dumaan dito, usually lactose-free formula ang solution, pero kung sinu-suka talaga ng baby mo kahit yun, best to check with your pedia kasi baka may ibang underlying issue na kailangan i-address, like reflux or something else. Have you tried slowly transitioning to the new formula, o bigla lang i-switch? A few of us nag-mix din ng formula with breastmilk para ma-adjust ang baby gradually, pero honestly, your doctor can guide you better sa best formula para sa kanya.