My sympathies Sorcha. I lost my two 18 year old cats within a few weeks of each other while I was extremely sick. A good friend insisted on my acquiring a new kitten after a while, now I have 2 again because I found that two felines together are much more than twice as happy as one.

May you keep pleasant memories of both your lost friends, and may you also find out just what it was that caused the sudden deterioration, so that you can avoid it with your next lot of 4 legged friends.