Dog retaliated by peeing on our bed!!!!!!?

We have a 8 month old mini schnauzer who doesn't like her nails clipped, but usually will allow it. This last time she really wasn't having it and we finally quit trying after 5 minutes. She followed us upstairs and peed on our bed in front of us. Did we push too hard? What's the best way to disciplain? How can we keep this from hapening again?