I'm so sorry to hear that, DK D: T_T If there is someone to blame for what happened, rather than just an unfortunate natural occurrence, I hope karma gets them.
I have an 11 year old shiba inu. He's still in decent shape, (arthritis, a small, but stable cataract in one eye that he's had his whole life, and a weird tumor in his mouth, that I'm hoping to get checked out soon, but no major internal problems) but I'm already trying to brace myself for when he leaves me. I have a 4 year old pitbull to help buffer the hurt when it happens, but it won't stop me from missing him.
Cuddling doggies to cheer you.