I'm so sorry you are going thru this stress. Like was said, take him to your vet and have a check up. Educate yourself on Yorkie health issues, watch for any possible signs, but don't dwell on it.
Enjoy your boy!! 
Just be aware and take care of anything that may come up. You may very well have no issues and have a long great life together.
Is that Laddy in your avatar? He's a real cutie! Post some pictures of him when you have time.