HELP LADIES ?! im a FTM my babygirl EBF and today my mom gave her less then two ounces of formula…

HELP LADIES ?! im a FTM my babygirl EBF and today my mom gave her less then two ounces of formula because she ran out of my breastmilk and i was at work she threw up 3 times since ive gotten home is it normal and just a way of her body rejecting the formula ? should i take her to the ER ?