Hello. A week ago, the baby inherited the baton from me and my husband…

Hello. A week ago, the baby inherited the baton from me and my husband and got sick with rotavirus. On Sunday, there was multiple vomiting, we had to go to the hospital. They gave an injection, took samples and sent us home. After that, for another three days, there was diarrhea, several bouts of vomiting, but I nursed him, the son hung on my chest all the time. He wrote quite a bit, there were no signs of dehydration, but on the third day he fell into the umbilical cord while urinating frequently, active and cheerful. Vomiting and diarrhea haven't been for two days, but the umbilical cord is still in. To the pediatrician only after a week, do you know why it could be