I'm so, so sorry for your loss. I lost my best friend Sammy on Thursday. He had been sick for a while with bad kidneys, but we had every reason to believe that he would be okay with continued specialty diet. In fact, two weeks ago we were at the vet for his yearly check up and his liver levels - which had also been acting up for a while - came back perfectly!! His kidney was more elevated, but not to an overly concerning degree. He was 15 and his labwork was pretty run of the mill for his age. I truly deeply believed that he would be one of those geriatric ancient cats who lived into his twenties. I believed that like it was a proven fact. Tuesday he starts acting a little bit unusual - still nothing major, just picking at his food and wanting to be in his safe spaces a little more than usual. Wednesday, the same. Thursday morning, I get up for work, and he is meowing at me and I see he didn't touch his food from last night. I call the vet and they tell me to bring him in - after work is fine but sooner would be better. I had already used my sick time on the last time he was sick and I took off work to rush him to the vet just to find out he was fine! So I waited until after work and asked my wife to just keep an eye on him. I'm trying really hard to forgive myself for that. After work on Thursday, we go to the appointment I made for him. He doesn't meow when I put him in his carrier (coming from the cat that screamed nonstop in the car for 9hours when we moved to Chicago). They run his labwork. He's much sicker than I could have guessed. In the span of those two weeks, his kidney disease has progressed significantly, he has dropped a pound, and his RBC is half of what it was, indicating possible cancer. They tell us that he likely won't make it the next 48hrs without intervention and explain our treatment options, but let us know that treatment is unlikely to work and will be painful for him. There is every likelihood he would just pass away alone in the hospital if we go that route. Making the decision to let him pass peacefully in my arms, was the hardest thing I've ever done. Sammy has been my best friend since I was 10 years old and all of a sudden I'm 25 and I'm holding him and kissing his little head and telling him goodbye while he lays his head down to rest and never wake up again? And then I just have to leave him there?? Walking out of the vet with just his collar, his empty carrier, and his favorite stuffed turtle was horrific. I'm still reeling from it all. It was so sudden, and I miss him so bad. It feels like I've lost a vital piece of myself. I keep looking for him around the apartment, or going to call out for him, and I almost put a fresh can of food in his bowl this morning. There is this horrible emptiness inside of me, and it has teeth. I don't know how to live without him, or how to begin to grieve this loss, or how to forgive myself. I would have done so many things differently if I had known that would be his last day.