PD-
That sounds like an awful lot to be going through. Unfortunately additional xanax will probably just cover up your feelings, which you'll still have to deal with eventually.

You know what, my dog has cancer right now too. They did surgery. Probably didn't get it all. If they can give her meds to keep your dog comfortable for awhile, then maybe that's the solution, at least until you're ready to say goodbye. Don't beat yourself up for being sadder about your dog. I would be too.

You can get through this, just be kind to yourself.