1st heat

Question
I have two yorkies. Female 5lbs 2oz and male 4lbs 8 oz.  They are 14 weeks old.  I know that it is early but my female came in heat and I think that the male got her.  I didn't know she was in heat because of her age. It was hard to tell because she also had blood in her stool so thats where I thought the drops of blood was from.  I took her to the vet who tiold me that she was in her second stage of heat. I thought puppies had to be at least 6 months before heat starts.

Answer
I don't think your female came in heat at fourteen weeks. Unless of course you're wrong or the breeder gave you the wrong information and she is really older than her papers say. In that case, she likely is pregnant. 9 months is average age for a female to come into season. If your vet is absolutely sure that she was in heat I would ask him for his opinion on her true age
Good luck
Cindi