My lab is within 2 weeks of having her pups. In the last 4 days she has slowed down. She is a very active dog. When she gets up, she seems stiff and has a hard time to get going. She eats and drinks, wags her tail and seems to be happy when she is near me. I'm wondering if anyone has had this happen to their pet. Is it normal for a dog to be this way before having pups?