Figure it's time for an update on The Shelbster. Overall she still seems to be doing ok. Especially for a dog who was diagnosed with Cushing's Disease and diabetes almost 2 years ago. When I took her to the vet initially, he didn't think she'd survive the weekend since she had an extreme case of ketoacidosis from the unregulated diabetes. The worst case he'd ever seen, actually, and he had already given me the "talk" about making a hard decision that night. She pulled through it though and is still kicking. She's a tough little dog.
I have been noticing a few things with her lately however. Her appetite wavers occasionally, she'll have low blood-sugar from time to time (and all the fun symptoms that go with that), and she's started dragging her right hind-leg a bit when she walks. When I got home from work this afternoon she appeared to be having some problems with that leg and putting her full weight on it. After a few minutes of walking around it seemed to clear up though and appears to be fine now. Weakness in the hind-legs is a symptom of Cushing's though, so that combined with her arthritis may be what's causing her problems.
After discussing everything with the vet, loads of online research, and long hours of internal debating, I opted to leave the Cushing's untreated in her. And I don't regret that decision at all. Given her medical history and health at the time, that was the only choice I could make.
She has good days and not so good days, but the good ones far outnumber the bad and overall she seems to be doing as well as can be expected. And hopefully that'll continue for a long time.
[EDIT (12pm): All of the above is true, but I can't get the feeling out of my head that something's wrong. There haven't been any big warning signs, just little things like dragging her foot, so I shouldn't be concerned. Yet I am. I'm convinced she only has at most, days left. Why do I always look for the absolute worst possible outcome in everything?]