When I bought Gracie, I knew absolutely nothing about puppy sizes and just went by what the breeder told me. I was told she was a teacup and was going to be tiny when fully grown. Well, she certainly isn't tiny! lol She's over ten pounds. I know the breeder was taking advantage of my lack of knowledge to make a sale, but I don't care at all! I wouldn't trade Gracie for a million tiny yorkies! I am so thankful for her and could not care less what size she is! She is precious to me. She just turned 8 months, and I recently got another yorkie. I believe he's going to be very tiny fully grown, but even if he's as big as mastiff, I don't care! Won't make me love him a bit less.
Just love your furbaby for who he is. There's just more of him to love than you expected!