pregnancy in yorkies

Question
I have a 12 month old yorkie and she had a heat cycle (I think)about 2 months ago.  I thought she was in heat because I touch her by accident and she had a black discharge.  We have a 1 1/2 yr old male that was riding her for about two weeks and now it has been about 2 weeks or so since and she has been affectionate and her belly seems a little puffy.  Her nipples protrude a little but not swallow.  Could she be pregnant.  I did not see them tie together.  Can you help me.

Answer
Hi Ellen

First, black discharge is never a good sign.  Are you sure it wasn't dark red?

If you have a breeding female it's so important to keep accurate records of her heat cycle and perceived cycles.  Otherwise you are in the position of is she or isn't she? And it would alert you to health issues that your female may have.  

Second, is this her first heat or second?

So if I understand this correctly, 2 MONTHS ago she came into heat.  2 WEEKS after that the male mounted. And it's been a month and now she's affectionate.

Gestation is 63 days. Because he was "riding her for about two weeks" isn't accurate accounting you will have to guestimate.  If the female allowed him to mount her for that length of time (typically it is within a short time frame) I would think that she had an infection confusing the male into thinking she was in heat.

The best advise and the one to ease your mind, is to take her to the vet for x-rays.