Urine question

I started keto using this app on February 1 and so happy I have lost 17 lbs and starting to get a bit of energy back. I love this app. I started on it because I was looking for a good program that tracked everything for my diabetes. What a lifesaver this app is!

I do have a question. I have noticed that I now have a bit of greasy substance in my urine and it is getting very dark. I drink a lot of water everyday. I am hoping this means my body is losing fat but I am a bit concerned. Will this hurt my kidneys and do others experience this?