Im so sorry for your loss
My 2nd yorkie passed away suddenly too. He was fine, then the next day he just seemed a bit off, but nothing that would be super concerning. That night he just wanted to cuddle, and he later passed away. There were no big warning signs. He was a terribly bred puppy mill yorkie so I'm just thankful we had him as long as we did
A new puppy won't take away the pain of losing your girl, but it does help to give you something to be happy about