What could cause vomiting immediately after food consumption randomly?

[KrKarl]

Small medical history here, I have had my Gallbladder removed when I was 15 years old. I had no problem with going through high school eating what I wanted when I wanted after the surgery.  I am now 20 and the last two year I have had trouble keeping my food down. I have been to the doctor and they said i just have flue. I also then began to think it was just the heat from being out side. I tried to avoid eating things that contained yeast, like French Fries, Potatoes, and biscuits. Nothing seems to work. I throw up randomly one day I can eat a plate full of fries the next day if i ate 2-3 bites of fries i throw up within 10 minutes. Just in this last week i have thrown up twice. At breakfast Sunday morning i ate three - four bites of biscuits and gravy, and a bite of sausage. Also on Tuesday evening I ate a 6 inch on flat bread chicken breast. I am sick of throwing up but do not want to get sent back to the doctor for"Flu." Flu doesn't last two years.