Could it be c diff? 4 year old being sick?

my 4 year old son last week had tonsillitis and scarlet fever, he was given antibiotics which ended friday, he recovered from that and then saturday night he was sick, (lots) sunday he seemed not to bad, no more vomiting, just a bit off his food, he started to recover from that and now tonight he has been sick (lots again). At my work we have c diff but i know this is usually just diarrhea, they only thing that makes me worry is that he has recently had the antibiotics which is a contributing factor in c diff, i have tried to call nhs direct for some advice but they are busy and only taking emergency calls??? i'm in the uk and its nearly 11pm so my doctors is shut, any advice would be great thanks