He may be a little bigger then the teeny tiny yorkies. But he isn't huge by any means. Keeley was 3 pounds at 10 weeks. The vet said he'd be about 7ish (I am guessing 8). But even 8 pounders are still small dogs!
Don't worry too much, I felt exactly as you described when I found out how much Keeley really weighed. I felt a little decieved by the breeder, but now (3 1/2 weeks later) I feel so much better and really don't mind that Keeley may end up to be a little bigger then I thought at first.
There are SO many cute Yorkies here that weigh around and more then 8 pounds and seeing all their cute pictures really helped me see that they are cute (and small) no matter how much they weigh!
Hope that helps.