HELP please?! I DONT WANNA LOOSE MY BABY<3?

I have a small dog. He's a westie- poo. (West highland Terrier Poodle Mix.) And he is fairly small, you know? Hes 11 now, I'm pretty sure. He's my best friend. I'm not just saying that. He really is, I love him so much. He is healthy, all thought he throws up more than he used to? How Long do small dogs live? I love my baby and I don't want to lose him.