While I agree that a vet should always be a valid option and a high priority in the case of any ill animal, you only have to look at what this lad posted a few pages back about his vet telling him 'ferrets don't get ear mites...'
While nobody on here is qualified to make a diagnoses, what you've still got is a resource containing a few hundred experienced ferret owners who between them have probably experienced nearly every single type of ferret ailment...
We could all probably give more advice than - Take it to a vet, even if it's just the basics like keeping the animal warm and hydr