If this started recently then drink plenty of fluids (clear soups, water
, ORS in water
, lemonade). 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.