Steve:
Not to minimize any of the pain, but maybe this will help. I offer this, since obviously, you're someone who, as I do, cares very much for our four-legged friends.
When you're ready, look beyond the immediate pain and sense of loss. As I mentioned above, about six months ago, ChiChi, the Chihuahua the kids just had to have got so sick with heart failure, we finally realized that NOT ending it was cruelty in and of itself. This happy image, and many others like it, will be with me until the day I get to join her in the endless green meadows of heaven.
As Gary Larson, the creator of Farside once drew, I hope she's enjoying herself, chasing delivery trucks made of solid SPAM!
Eventually, the pain recedes a tad, and before you know it, there's room in your home and heart for a youngster who needs a loving home. And so, meet Mimi.
As an aside, I used to be a big dog guy, having grown up with a Husky and an Airedale. Long story how we got to these, but no complaints now. My definition of a Chihuahua: a five-pound dog who has no idea she's not a timberwolf.
Again, hang in there. Always enjoy the memories of your old friend.