I think you sound like a wonderful pet parent! Honestly, I have two yorkies, one more active than the other. I am away from home working appx. 10 hours a day, but I believe my pups are happy with their morning yard time and evening yard time x 2. Of course, we do some inside training exercises and mine both enjoy toy time. Most importantly though, they both just want to sit in my lap or snuggle next to me.
Please take care of your own needs, that way you can continue to take care of Johnnie. I bet if you think about it, when you arrive home after an outing and Johnnie greets you, that is the happiest time of day for both of you
Also, join us here at Yorkie Talk! We are each "Yorkie Crazy" and someone is always available for a chat.