I had a possible stomach bug that presented with a lot of growling and nocturnal diarrhea often with undigested food. it mostly resolved after 2 weeks, but now, about 5 wks later am getting it again, not nocturnal, but w/nausea and large loose stools?

Diarrhea: A viral intestinal infection usually doesn't recur. Because diarrhea has recurred you could be dealing with other type of intestinal infections, irritable bowel syndrome, gluten intolerance or inflammatory bowel disease. A stool culture for pathogens can be ordered. Avoid harsh roughage and take kaopectate (kaolin and pectin) in the meantime.See a gastroenterologist as needed.

See your physician: Your symptoms are concerning and you should see your physician for evaluation. Nocturnal diarrhea can be a sign of an underlying illness. There are many possible causes for your symptoms, but giving you a long list of possibilities won't be very helpful. Don't try to diagnose your condition on the internet. You need to see your physician.