My boy had parvo at 8 weeks old. Spent 5 days at the vets. He's now a perfectly healthy, huge, 85 lbs, GSD male that doesn't take crap from anything. I know its rough, but each day that goes by is a good sign. Once they can make it 3-4 days its a great sign. Still could go bad, but generally at that point the dog will pull through.
I strongly suggest spraying your whole house down with a bleach solution. 1 cap to 1 gallon of water is what the suggested solution is. Bleach is the only thing that kills parvo.
CD RE TC HIC 7/10