Hi welcome to health care magic... You can have here drug induced gastritis as per history provided.... Stool examination done in your case... If no pus cell and no parasites seen than no active specific drug needed... Take Rabez DSR like drug contain rabeprazole plus domperidone for gastritis..... Avoid high spicy foods and excess tea, coffee... Cooked oatmeal help in soothing stomach... High fatty diet restricted for few days More water and maintain hydration... If no improvement in few days than USG done for further work up Physician consultation advisable for examination and further work up