I agree with BamaFan and Ladymom. I would get two Yorkies so they have company. You also can't potty train if you aren't home during the day.
Seizures are not normal. The first three things that come to mind are hypoglycemia, hydrocephalus and liver shunt. I would go to another vet and/or return the pup if you don't have the time or resources for this one.
