My nephew had viral meningitis.He projectile vomited in the morning, he was drowsy all day.An on call GP came out to see him later in the day and diagnosed a lung infection, by the time my brother had been to collect the script from the pharmacy he had to call for help again, he deteriorated within half an hour.Photo sensitive, stiff neck.He took him into hospital himself on the GPs advice as it was quicker than an ambulance. He was fine after a few days under obs and recovered fully.
So guess what i'm saying is that you acted quickly, you did the right thing and he certainly is in the right place. It's a terrible worry though, it sounds more viral (anything) to me but i'm just trying to reassure you, i'm not a doctor.Keep us posted and try your hardest to relax x