Noro virus

So, my daughter has been around a bunch of my family members this weekend. Two of the people she was with have come down with Noro virus (severe diarrhea, vomiting) in the last 12 hours. I'm very worried she's been exposed. If she does start to have symptoms, what do I need to watch for? I know dehydration is a big risk in a young baby when diarrhea and vomiting are involved. How do I know when she's dehydrated? If she does get sick I know I need to nurse as often as possible to keep her hydrated. Anything else I can do? Really hoping we dodge a bulletin with this 😷😬😥