Talk to Pediatrician on Fluctuating Fever

My four years old son has had fever for three days. It keeps fluctuating between 99-102.. He passes stool a bit more than usual (but not too many times) with some pain in the belly and complains a headache and tiresome.. He became alright in between and it appeared as nothing has happened ever.. But this time the fever has touched 103. Does it sound something particular or just a seasonal thing.. I plan to take him to soem child specialist this evening, but what should I do till then?