I would take him back to the docs again!
He's obviosly not getting any better, Ok he may be eating but if he's being sick then thats not very good IMO?
You can never be too careful!
I've actually just spoken to my friend thismorning her LO has been sick for a week, she took him to out of hours GP on friday and they said he was 'fine' he's being sick and has bad nappies too! She's taking him back today and demending they do something!!
Hope he feels better soon

Poor baby!
xx