My dog, Hartly, became sick yesterday, Friday. He started with diarea and then vomitting. He can't keep anything down.
He is a 10 year old yellow lab mix, who has always been in great shape. He weighs 45 to 59 pounds. He has all of his shots. Today is Saturday, and no change. He can't hold down even his dog treats.

I would recommend you get to the vet today. Without a physical exam, we can only guess. Is he drinking and urinating normally?

Ditto, a vet visit is in order. This could be anything from gastritis to a blockage.