20 minutes after eating i had heart palpitations headache abdominal pain diarrhea and nausea. i also feel feverish. whats going on?

Reacting to gluten?: This may be caused reaction to gluten. Try gluten free foods and see if it will help. Also, if you are fatty foods, you may develop a condition called "endothelial dysfunction" i.e. Sluggish arteries with blood flow problems. So eat healthy, minimize fat, refined sugar and foods with gluten. You may feel better... Good luck!