We stopped tallying up the bills long ago. Too distressing!
But all dogs are good, and worth it, so we just keep paying our bills...
Sounds like she's doing very well! Pred will cause thirst and excessive urination--and our dogs seem to feel hotter when they're on it, too--so I suspect that's why she's a little 'off' in that regard. How long before you can wean her off the pred?