I have a 13mos. old daughter who, over the past 3 days has "gagged" everytime I give her foodshe refuses to eat. She is drinking and stooling fine, and our family doctor says not to worry, but how long do I let this go? She is normally a playful happy little girl and is now fussy and over-dramatic. Her strep culture came back negative, and I'm a loss. Please help.