Aw, frustrating talaga yan, especially pagkatapos mahanap mo na ang formula na gumagana! A few of us moms have gone through the same thing, and honestly, sometimes it takes a few tries bago makita ang improvement, may babies din na mas matagal mag-adjust. Since baby is 10 months na, you could also try introducing more solid foods na may fiber like banana, oatmeal, or brown rice to help with the consistency ng tae, and make sure siya's getting enough water in between feeds. If it's been a while na and the loose stools are paired with anything else na off (like fussiness or rashes), best to check with your pedia para sure lang na walang allergy or intolerance happening, especially since you switched formulas.