A rescue dog is so rewarding and an adult especially if housebroken is sooo much easier than a pup. Submit an application as soon as possible to be sure you are approved. If approved, you'll be ready when you see the dog you want online.
These sorts of things happen so quickly, and unfortunatley there is no "Undo" button. I think it is easy to get complacent in our lives. We get use to routine and every once in a while things just happen. So sad.