This ferret needs to have an emergency appointment today.  It can't wait.
When a ferret does not eat, doesn't go the bathroom, and is flat then
there is a chance of several bad things including a complete blockage
(most of which don't show up in x-rays).  In such a case a phone call
to the office saying, "The animal is in very bad condition and can not
wait." should get an emergency appointment.  Complete blockages can cause
toxins to be formed which can be fatal within 48 hours depending on the
ferret; if it goes too long even the window within in which surgery can
help goes away.  With symptoms this extreme I'd go with only what the
treating vet says and I would insist on having an emergency appointment.
 
Mary Ann, either cover the fake fleece or remove it.  That stuff can
build into fake fiber "fur" balls and you indicate that he is ingesting
it so that's a bad combination.  In our ferret's case such conglomerates
were not known to be in him until they had to come out.  His habit
and his stools definitely should be discussed with your vet as you
plan to do.
 
Oh, something that can sometimes be useful to know: things that cause GI
inflammation like such partial blockages can also at times affect nearby
organs so it is possible now and then to have occurrences like finding
the liver values being off but the liver itself is actually okay.
[Posted in FML issue 4148]