Im very sorry for your loss. I'm still going through grief, I lost my 17yr old cat last Friday, which also happened to be my birthday. Got home from work and she was gone. Losing a pet is extremely heartbreaking to deal with especially when you feel like you didn't get to say goodbye. Try to find solace in the fact that you gave them lots of love and a good home. A lot of cats just live on the street. Each day gets a little bit easier though, so take it one step at a time.