It sounds like it to me...yorkies tend to get extremely attached to their main owners. Probably because you take such good care of him
My yorkie who was stolen from me 3 years ago was very attached to me like that. I once had to go out of town and couldn't take him (usually I took him everywhere). My aunt watched him for me and he threw a fit!! Where's my mommy!!! Chewing, crying, all things he nevvvver did at home with me.
Maybe someone on here has some training tips for you. I would love to know this as well. It would definitely be less stress for the both of you if he can be "ok" when you are not around. Maybe a bully stick? Or something else that he can get into for a while and relieve anxiety? Sorry, I don't much advice for you. Just empathy