Are pale and yellow stools common after having a stomach bug (vomiting and diarrhea)? I am 5 weeks pregnant also.

Possibly. Light brown or yellowish stools may be seen with loose movements due to rapid transit through the intestines. However lack of pigment in stools may be due to malabsorption or blockage in the biliary tract. If the urine is brownish it suggests bile obstruction. Discuss this with your obstetrician as needed.