So sorry for your loss! I know what its like to lose a beloved animal. I was 6 when I watched my Mittens give birth to Boo-Boo. Boo and I grew up together, and I put her down 17 years later. She lived with diabetes for almost 10 yrs. Now I have my Minki, Dixie & Gizmo, my beloved children. Try if you can, to open your heart again and find a new friend at an animal shelter. It will never replace Simon, but you'll give another baby a chance at a good and loving life.
Take care... Steffi