You're doing an amazing job with Yen
it's exhausting looking after sick piggies & to have been doing it for nearly 2yrs is a credit to your devotion to her
Just a thought... But I used metronidazole for treating a fish years ago, it came in liquid form & was very expensive -but it worked relatively quickly .
Years afterwards the vet prescribed tablets that I had to soak, mush up & dissolve into the water because they were a fraction of the price. This was more of a faff & not half as effective. Just wondering if it would make any difference to Yen which form it was given?
You know her best & it's obvious that you love her dearly and want what's best for her,so go with what she's telling you, what's her quality of life - is she happy doing guinea pig things?You'll know in your heart you're doing the right thing whichever option you decide.
Thinking of you,big hugs
Make sure you take care of yourself too. Xx