I’d take my dog to the vet after more than one day of vomiting and fever. Period. You should make certain she is well hydrated. Low Sodium soup broth is a good way to encourage drinking more fluids. She should have a blanket to keep her warm, too. Do you know why she is throwing up? Does she have a virus? A bacterial infection? Animals need doctor care when they are ill, more readily than humans…WHY? Because they can’t tell us they’ve eaten poison, nor can they say “I’ll be okay if I just sleep it off for a day”. A vet would get a blood sample, stool sample, and take her temperature and could most likely diagnose her during the same visit, then give you antibiotics or some other meds to help her get better quickly.