try taking some antacid to settle your stomach. eating an apple also helps, don't know why. Also drinking more plain water. Stay away from coffee and alcohol, as likely to inflame the stomach lining.
Can be a stomach/intestinal infection. Call your clinic and talk to your Dr/nurse and ask if it seems worrisome. They'll probably tell you to wait a few days to see if it clears, otherwise you may need antibiotics. Otherwise, not indicative of a major problem.