Aw, that's a big change talaga from her usual pattern, mama! Yellow poop is normal for formula-fed babies, pero kung suddenly nag-increase siya to 4x in a day when she's usually just once, baka may minor tummy upset siya, could be the formula, or she's just having an off day, or something she's reacting to, kaya I'd really suggest checking with your pedia just to be sure, especially since she's still so tiny at 2 months. A few of my mum friends had babies na nag-poop more frequently for a day or two and it was nothing serious, pero better safe than sorry with newborns, right? Watch din kung may fever, fussiness, or if she seems uncomfortable, those would be red flags na kailangan agad ng doctor.