My son has had a hot & cold fever for a few days, this developed into a sore throat and now he has a stomach bug with only nausea, he hasn t eaten anything today and has a stomach ache, he only ate an orange and had water which made him sick, he feels very hot just before he gets sick, then he feels sleepy after but still has lower stomach cramps, is this a virus that will work through his system or should i get him to his GP?