Learning about Parvo

I learned a lot in the last 2 days about Parvo. When I bought Toto I was guaranteed verbally by the breeder that Toto had been given all his puppy shots and was only 11 weeks old. He in his ad said Toto was 9 weeks old. I found out by email from his girlfriend he was 13 weeks when I bought him and too old for ears to be cropped. I talked to the vet the day after I bought him and the vet said he was in good shape. He said Toto would get another Parvo shot at 16 weeks but this was before I found out Toto's true age. Toto was doing great running up and down the stairs, chewing on everything.. being a typical puppy. He was fine yesterday morning but suddenly within 3 hrs after being awake, he got sick. I called a vet at Pet Smart since I was new here to Colorado Springs and talked about Toto's symptoms. They said just make sure he gets water and bring him in on Monday. I messed up by not getting a written contract nor copies of his pedigree and shot/medical records. I'm just hoping and praying that he'll survive this bout with Parvo. I don't think I could handle the loss of another pet especially this soon after losing another one. I'll also be checking a breeder before buying another pet and not buying on a spur of emotion and so soon after the loss of one.