Hang in there, you are doing your best for her, and I hope she starts to improve. SubQ fluids can really increase energy/alertness, so I imagine they increase comfort for a cat as well. I thought I'd share:
I have an acquaintance who is a type 1 diabetic and I was curious about the experience that a cat might be going through during severe DKA. This friend of mine had been diagnosed about 10 years ago, and had gone through DKA herself twice, very severe the first time. I asked her what it was like. She said the thing that she remembers most is that she was so thirsty. She said for the most part she was too out if to care a lot about what was going on, but remembers feeling nausea and extreme thirst. She denied that the experience was painful at all, but said she was to tired to move, and just very out of it. I think it's helpful to hear someone's take, because our cats can't speak for themselves.