Mama, ang greenish-gray poop is usually normal sa mixed fed babies actually, pero yung pattern mo (consistent for 3 days + watery na ngayong Tuesday) ay worth checking with your pedia, especially since nag-change ang consistency niya, better safe than sorry talaga! One of my mum friends had similar greenish stools with her mixed fed baby at it turned out she needed to adjust the formula ratio, so it could be something simple like that, pero mas better kung makita ng doctor para sure na okay lang si baby and walang gasto na unnecessary worry mo.