What Causes Fever Along With Vomiting And Stomachache?

Hi, my 6 year old daughter has been ill with a fever for 2 days and vomitted this morning(water). She is complaining her head feels funny, and that her stomach is hurting. I notice an odd smell to her breath(?ketones) and wonder if I should take her to a walk in clinic, or just keep her resting. Her temperature seems to have leveled out at under 100 F. She hasn t eaten much of anything, just gingerale and water since Saturday.