Could be a lot of things but your pup is indicating she is in a lot of pain for some reason and something is wrong. Put her in her kennel while you call your vet or emergency clinic to talk to them about it since she is limping. Do you think it's a leg or maybe her stomach or something else or more than one thing? Your vet will have a better idea after an exam and talking to you. Hope your baby is feeling better very soon.