had a dog that I let get pregnant and yes at times they just like humans go through morning sickness and being tired. Keep the appointment with the vet so that blood tests and so on can be done to rule out any problems and know those tests might just come up that the bables are taking all her energy (iron and so) so the vet may have you like they did in my case have you giving doggie vitamins just like a woman who is pregnant is put on penatal vitamins when pregnant. hang in there