I felt the same way after EVER single lose...but like they say, it's better to have loved and lost, then never loved at all. Except it's MUCH more worth while with an animal, because their love is unconditional. Doesn't matter who, what, where, or why...they'll love you, if you love them. They're good for the soul, and make you happy when your sad.
I swore no new pets after the last one got put down, but after a while,
You Miss the pitter patter of little paws, and the stupid annoying shit they do...like walking across your keyboard when you're trying to make a post. Or biting your toes at 3 in the morning, because they're up, so you should be too.