I was wondering if anybody knows if post-partum depression can happen in dogs 3 weeks after giving birth? Yesterday our puppies turned three weeks old, and Lana has not really been herself for the past two or three days. She leaves her puppies for two or three hours at a time, sometimes she goes out to play with the other dogs, but usually just goes and lays on her pillow all curled up in a little ball with the saddest expression on her face. Or could it be that she is just tired of puppies? Other than that, she eats, she plays, she does everything normal, but those bouts of sadness concern me a bit.