Not eating

Kate has a stomach bug Friday night but it only lasted about 12 hours. She hast thrown up since Saturday morning around 8. Since then she has barely eaten. She will eat a few ounces here or there but will go up to 5-6 hours between. Like she ate 3 oz at 10 and has only had 1 oz since then. She seems to be having a decent amount of wet diapers but should I be concerned?