Irritable Bowel Syndrome
is a diagnosis of exclusion, meaning that doctors have to be able to prove that there is nothing more serious going on before they can tell you that you have IBS. That is because IBS then becomes an explanation for a wide variety of symptoms that you may have in the future, and doctors will not have to constantly test you on every new occasion of loose stools or changes in your complaints. You should definitely discuss your concerns with your doctor
As for your current symptoms that you are having, the best way to tell between a normal infectious cause of loose stool and IBS is by your history. Have you eaten anything new or tried a new restaurant? Are others around you also ill? Do you have a fever, abdominal pain
, or vomiting that may be symptoms of something else? Are there other symptoms that are concerning to you or your doctor? Any of these would or may be more likely to be signs of a stomach bug. If, however, your symptoms are otherwise nonexistent and you only have a worsening of your usual loose stool, then it is quite possible that this is just an exacerbation of your existing IBS. As always, please speak to your doctor.