I'm sorry... I forgot to say that her nipples are erect and larger than normal and the vulva is still slightly swollen from when she was bred. My husband is taking her to the vet tomarrow to find out for sure. Thank you for your help.
Linda
She should have begun to show signs of nipple enlargement as well as swelling in the vaginal area. Some dogs, like some people hide their pregnancies and don't show until the very end. She may have only one or two puppies, in which case she wouldn't grow very large. An X-Ray or abdominal ultrasound/pregnancy check is really worth it, not only to set your mind at ease, but to determine a more exact due date, or to see if she really is pregnant.