I do understand the frustration, Andrea.  This kind of situation is
incredibly painful.
 
I'm guessing the vet's guessing.  Sometimes, there's just not much in the
way of obvious symptoms to put a finger on a diagnosis, and the vet just
has to revert to the list of most likely suspects.  He has to apply "do
no harm" first, sometimes with no way to know that doing nothing IS doing
harm.
 
I'm not a vet and I'm a lot more likely to be wrong than he is, but I
doubt lymphoma alone would have caused such an abrupt decline.  And if
it is lymphoma, it was probably already too late on the 10th.
 
Hard stomach and no obvious tumor on the ultrasound... I'm not sure how
experienced your vet is with ferret ultrasounds, but if there was a tumor
of a size to cause a hard belly it would most likely have been seen on
the ultrasound.
 
How's pooping?  I'm thinking more on the lines of intestinal tract
blockage... maybe with gas behind the blockage causing the belly to be
hard.  Blockages can be hard to spot on ultrasound and sometimes even on
xrays depending on the blockage material.  That could definitely cause
an abrupt decline.  It's also sometimes difficult to diagnose as a need
for emergency surgery.
 
My prayers are with you.
 
Ferret food comparison chart (love this... it's printed out & given to
all my potential adopters):
 
http://www.ferretstore.com/ferfoodcomch.html
 
What Suki said: Don't force feed until it's the only option.  And then,
take your time, take it slow, don't try to do it all in one sitting.
 
See this web page:
http://www.ferrets1st.com/articles/force_feeding_photo_guide.htm
for photos to help.
 
Read the complete 'Feeding a Sick Ferret' for tips on the steps you can
take before having to resort to force feeding here:
http://www.ferrets1st.com/articles/feeding_a_sick_ferret.htm
 
Debi Christy
Ferrets First Foster Home
http://www.ferrets1st.com
[Posted in FML issue 5126]