Yes, this is most likely a seizure. I've seen a lot of seizures in Yorkies and they can look very different.
What you described is your baby as he moves through the various stages of a seizure.
The nervousness, seeking affection, and glassy eyes you are seeing is actually the beginning of the seizure called the aura stage.
The actual seizure itself is the Ictus stage. What you are describing sounds like the typical generalized tonic clonic seizure. The tonic phase is when he become stiff and falls over. Next he would begin to shake or paddle his feet and may cry out. This is the clonic phase.
The final stage is the post Ictus stage which occurs after the actual seizure. They will typically vomit and be very tired for a few hours.
How old is your baby? Typically if a dog experiences his first seizure before 1 yr old or after 5 yrs old, there is an underlying cause. If a dog experiences his first seizure between 1-5 years then it is typically Idiopathic epilepsy which means no known cause. Regardless, your vet needs to run some tests and rule out any obvious causes.
Take a look at this post where I described more about seizures and when they are life threatening.
http://www.yorkietalk.com/forums/sho...42&postcount=4