I also have had a number of cats that lived in/on the physical plane with me, and a couple that came back across the divide at times of great need by myself, so yes, Midnight and all of your Guardian pet souls very well are right beside you. Unfortunately, kidney failure is a common disease suffered by both cats and dogs. If you want to tryto protect your pets in the future, try to get them used to brushing their teeth at a young age, as a great deal of Kidney failure is caused by poor dental health. As I learned a couple of years ago with my own cat.
My cat is still alivefor now, but I'm trying to ready myself for that eventual day of loss. I'm truly sorry for loss, and I know it's hard at first, but remember that there are a lot of pet soul mates just waiting for someone to make them a forever guardian spirit.
Love and peace!