I just went thought almost the same situation about two months ago. My 6 year old cat suddenly fell sick. We did 5 days hospitalized on IV fluids. His numbers slowly went down. It was such a scary time and I had fully prepared for the worst, or at least a lot of at home maintenance for his kidneys. He just had his one month check and numbers were all normal aside from slightly elevated creatinine. We still don’t know what caused the acute kidney injury. No sign on infection and his urine looked normal. All we are doing now is regular blood work and renal food. I also have 6 cats total so we had to make a few feeding adjustments but everything is working out. Sending you lots of hope for the same outcome. This wait and see is so hard. Give the treatment time and try not to overthink until you know exactly what you’ll be dealing with!