In such a case, it is best to let the symptoms pass. In fact, the diarrhea caused by gastro is one of the most effective ways to protect the body by allowing the "germs to get out." Using a product like Imodium™ in such a situation would at least partially prevent this protective mechanism.
So, if your diarrhea has not been present for more than 3 days, or is not accompanied by blood in the stool, there is no need to worry. Rest, drink a lot of water and rest again. We also avoid irritating foods (too salty, sweet, spicy).
For belly pain, the good old hot water bottle!
If symptoms are still present in 3 days, or if blood were to come out of the rectum, we will need to consult a doctor.