Please Help Save My Dog's Life

I've never done anything like this. I would normally never ask anyone for anything but I really need your help. My name is Josh and 7 years ago I almost died. I was on drugs, homeless and suffering from a deep depression for what seemed like as long as I could remember. I frequently had thoughts of ending it, just giving up on life. Then out of nowhere this loving, caring ball of fur fell into my life and changed me forever. Those of you that know, or have met Cashy, know he is the sweetest (90#) lap dog anyone has ever known. He loves everyone and everything... well except squirrels and sprinklers lol. I am starting this gofundme because Cashy has become very sick and I need your help. 2 or 3 weeks ago Cash started being really picky with his food which has turned into him not eating anything at all. He has lost 27#'s in the last month and can barely walk. I spent every dime I had taking him to the vet. I even spent my rent money. He has something going on with his kidneys and the hospital wants to admit him and run some tests as well as feed him intravenously to help him get some energy back. For 3 days of hospitalization, tests and feeding I'm looking at close to $3,900 not including any additional costs for treatment. My dog saved my life, he is everything to me and I'm trying every possible thing I can to try and save his. Please please please help me.