yea its always sad to loose a pet; ive had many pets come and go over the years and even though they can never be 'replaced' you should probably get a new kitten. You have to remember the good times and realize shes gone forever. Know its not your fault and theres nothing you couldave done to save her. I think you should get a new cat, or maybe two and welcome them into your family the same way you did for sushi, im sure they will grow on you the same way he/she did.