I'm so sorry for your loss. Even though I had my kitty for 11 years, I didn't expect him to go so suddenly. He was healthy on Saturday, and we put him to sleep Wed morning. It never makes any sense, and I could have written almost your exact post two days ago. My first day, I couldn't even accept it as reality. There was just no possible way that it could have happened. I cried and cried. I couldn't eat or drink or sleep. I felt so silly, because I couldn't even think about vacuuming up his pet hair off the floor, that it would some how remove him entirely from our home. I wanted to cling to every little bit of him. I just couldn't come to terms with it.
This website really helped me. I knew I was not alone, and that people understood the immense grief I was experiencing. Everybody here, is here for people like me and you. We know that one day, all the sad last moments will subside, and we'll remember more and more of the good memories. Even if we can't imagine that time right now, it will come. Talk it out here as much as you need to. My heart goes out to you and your family.