Puppy Recovering From Parvo Sick Again?

She made it. My 7 week old German Shepherd puppy survived an outbreak of parvo, in my litter of 8. She was the only female and the runt. It's been 7 days since she's been eating, drinking, running, and playing with no signs of Parvo at all. Today she's thrown up twice with grass in it along with her baked chicken breast and a little dog food mixed. I am scared to death she is going to die. I've been a responsible breeder for 7 years and never lost a single puppy. To say the least, my family is devastated.

Here are my questions. She's been healthy in appearance for about 7 days. She's had the two week antibiotic shot from the vet and Paxxin. Is there any related secondary disease commonly associated with parvo that she could be getting in her particular situation, keeping in mind she's had the two week antibiotic shot? Could she suddenly get worse all over again and die? Because she can't do that it will destroy me. And finally is it just part of her healing and she's going to have days?

Please no holding back. I truly need to know so I can handle this. Any information and experience is very much appreciated. Thank you.