If she's reviving a day at a time, that's probably a good sign. If she actually has a UTI (which she may not: some dogs just have crystals in their urine), she should be on an antibiotic. Ask??
What's the weather like? If it's very not, that could affect her appetite, just as it affects humans.
Ruby the Corgi Pup came down with a UTI shortly after she arrived here. I'm told corgis are prone to them. Vet dosed her liberally with antibiotics -- it took a while, BTW -- and put her on the P/D. Over the course of a couple of months, she shook off whatever ailed her and resumed growing normally. She's now the same size as the elderly corgi -- about 20 pounds -- and brimming with health. So, I suppose...be patient. It takes some time to throw off the bug.