completely agree with PP. that's an almost 9% loss by my calculation (125 to 114). when DS was born, they wanted him to lose less th vn gfvrk oops baby on the keyboard less than 8%, i think up to 10% is still in the realm of normal. so watch his wets carefully but otherwise do exactly what jomo says!
i'll add: my milk didn't come in in force until day 5, which exacerbated their concern for DS (even though day 5 is still well within the normal range). we ended up feeding an oz of formula, twice, on day 3, using an SNS. it was REALLY hot, ds was REALLY unhappy, and i'm very glad we did it. in retrospect i wish i'd asked someone i knew for donor milk instead of using formula, but i'm glad i gave him something. using the SNS meant that i was still letting him bring in my milk.
Nursing, pumping, cloth-diapering, babywearing, working professor mama with the awesomest SAHD ever.