You could be suffering from
viral gastroenteritis or from food poisoning. Eat light, do not stay hungry but eat simple things like toast, porridge, cereals, crackers, banana, rice, peeled apple, etc. Take over the counter antacid and antiemetic (this SOS for vomiting). Watch out for a day or two with this treatment. If still the symptoms persist, then you may need an antibiotic for the gut and would need to see a doctor.