Good evening Business Tutor,
I understand your concern for your Little Yorkie. Let me start with the Vaccinations. It is not uncommon for little dogs, like Yorkies and Chihuahuas to get very sleepy after their vaccinations. I have a little Chihuahua that will sleep for two days after she goes in for her booster shots. As long as your baby is not vomiting, having Diarrhea, and is eating and drinking, your little girl should be fine resting out the Vet. visit.
As far as the heat cycle as with most dogs we expect their heat cycles to be every 4-6 months, but some dogs can go as long as12 months between heat cycles. It is all in the Hormones as the body ages. Here is a link that describes what one owner is going through.
http://en.allexperts.com/q/Dogs-701/yorkie-heat-sessions.htm
The last thing I would like to address is, that you know your little girl the best. If your Vet. does not want to listen to you about your baby, and you feel uncomfortable with the care you are getting, you should change to someone who will respect your knowledge about your little girl and her body and her cycles.
I hope I have addressed all your concerns this evening. Respectfully, Joan Jav917
