Unless a puppy has been raised sitting in their urine, they don't want to lay in it...so she very well may have a urinary tract infection, in which case she will feel an urge to pee far more often than is normal and won't be able to hold it. I'd have her checked for that....take a first-pee-in-the-morning sample to the vet with you and have them check it for infection. A soup ladle is a great way to catch a urine sample..
