@Kizocha, I feel your pain. This happened a year ago but whatevs. So--- I have had this dog for all my life. He was fifteen(just a couple years older than me), but then he could barely whine. So, one day, my parents said to me, we are putting him down. I cried myself to sleep that day and all the others. Still sometimes I cry. So, Kizocha, just know that your cat had a very happy life, but as all things come, they all have to go. So what we did is we adopted a new puppy. Now he is 3. And he is HUGE. He weighs just a little less than I do(somewhere around 100lbs).
Now, don't worry, be happy. And always remember that your cat went to heaven, a happy place, and there it can get and do what ever it wants. Now get a new cat and love it as much as you loved your old one. Now go and be happy ;).