So yesterday we found out the reason our dog was acting so lethargic and unwilling to walk or navigate stairs was because she had a UTI. They gave her some meds and sent her home. Fast forward to today, and she still had no appetite, which means no way for me to get the meds in her. I said "screw it" and took her back to the vet to hopefully get an injection of antibiotics. Good thing I did. She was running a fever of 106.6 and she was essentially dying. They're keeping her overnight hooked up to IVs, but the fever's already gone and she's a lot more alert and responsive to their attention. Looks like she's going to pull through, but goddamn that was close.