As Jamie said, "We've all been there ...".
It does not make it any easier, no matter how many you loose, each one is precious to you. Just be thankful you are the type of person that really does love her little ones ... there are so many that do not ... I almost feel sorry for them because they have never felt the bond between themselves and an animal ... it's a love/bond like none other and your life is richer because of it. Your heart hurts because you care, but all the animals you have had or will have (including your own children) will feel a special kind of love, just because you are their caretaker. There could be any number of reasons this has happened and animals have a heaven, too ... or at least that is what I believe ... and they are now free to run, play without a worry. No pain, no illness, no predators and no cages, once they cross the Rainbow Bridge.
Big Chinnie Hugs
Jo Ann