At that age, some babies do have loose stools and the colour can vary between green and yellow depending on the formula and how their gut is settling, so it may not be anything serious. That said, watery stools that consistently leak out are worth a closer look, so it would be good to bring her to the PD just to rule out things like a formula sensitivity or an infection, especially since you want to be sure she is absorbing enough nutrients. The PD can also advise if a formula switch might help, since some babies do better on a different type.