Lucy,
you did the right thing. Although, it is always the most difficult thing. You gave her shelter when she needed it most and she gave you companionship in return. Nice that she was generous enough to share herself with your other neighbors, too.

Our only responsibility to our pets is to love them as much as we can when they are with us and, when it's time, to let them go as painlessly as possible. And, of course, to never forget them. If there is a "kitty heaven", then she's there now telling everyone what a great co-mom you were.

We know how you feel. We share your grief.

Jim