yep...i'd try consulting the vet...sudden changes in behavior can be signs of something but after consulting the vet..and it's nothing but behavior problems (no medical problems), try feeding her earlier. I find that feeding Kai right before bed time will keep him up. Also, try doing a bit of exercise before sleep. This will tire her out. It doesn't necessarily have to be physical activity..it could be mental activities...like reviewing your training...or hiding her toy and letting her find it..or you can try what me and Kai do..and that's hide and seek. He loves it and caught on fast because it was really fun for him. I just hid behind the door (out of his sight), and said "Find Ashley!" after about 5 minutes, he caught on.