I'm sorry to hear about Sadie's not feeling well.  I don't know if this will
cure your problem, but we occasionally have to deal with hairball issue
ourselves.  What we have found works when our little fuzzies seem to have
some sort of congestion is to give them a teaspoon of vegetable oil.  Also,
we mix their food with a little bit of water, and we brush them out a bit to
get rid of any loose hair.  However, our Chubakah recently was not cured by
this treatment and the vet reported that he had some sort of virus and he
was better in a few days with some medication and the iv they had given him.
His poop, too, STANK!  and he had thrown up.  So if the oil doesn't work,
he may need your basic ferret penicillin.
 
I haven't introduced myself before.  We live in MA and have 2 babes, Minny
(a beautiful cinnamon, 3 mos.) and Chubakah (handsome sable boy, 9mos.).
We had to put our beloved Taz down a few months ago for adrenal tumors (our
hearts still ache) so we understand being gunshy when the critters get sick!
Hope this helps!
[Posted in FML issue 2359]