If this is a case of stomach flu, the abdominal cramps should be associated with both or one of the dominant symptoms of stomach flu, vomiting and /or diarrhea.
Symptoms of stomach flu, usually, start suddenly and may last 1 to 10 days, but, often the episode is completed within 3 days.
It seems like this abdominal pain is only due to IBS.
Abdominal pain due to IBS can be acute and/or chronic one, with quality of cramps or diffuse dull pain, located in different parts of the abdomen or felt generally.
You may feel upper abdomen pain, often associated with bloating and may worsen after meals.
Cramping can occur around the belly button and through the lower abdomen.
Lower abdomen pain is most likely to be eased by a bowel movement.


Best wishes!
Marija