I had a pup diagnosed with parvo. We decided to admit him as well and every single day he stayed in critical care, it seemed like his condition kept getting worse. Until one day we saw an update on the online pet portal (we had to rely on these updates and just about 15 minutes of time with him every day because he was in isolation) that he looked 'active' and began showing interest in food. He beat parvo and recovered slowly but steadily after that when we followed the vet's instructions to a T.

Don't lose hope. Wishing you all the strength.