Maryanne, I am so sorry for the loss of your beloved Kelsey. Freeing her of her pain is truly an act of love. It's a very selfless act. Many people cannot bear to do it, even when they know it is the right thing.
When my Quincy died, I didn't get another pet right away. I didn't want to replace him. It's wierd, though. I saw him dead every single time I closed my eyes for a whole year (he died in my arms). But after that year, I got a new pet. Starting that very night, I didn't have that vision anymore.
My advice to you is to not think about getting a new pet right away. You will know when you are ready. And, who knows, your next pet might just adopt YOU. That has happened to several people I know who have lost their beloved pets.
(((Hugs)))
Lynn