I am really sorry. It is tough to lose a pet you care about.
I would actually disagree with Soulguard's advice. Take the time to grieve for this cat before you get another one.
Poor advice from soulguard is nothing new, alas.
The single most striking characteristic of dogs and cats is their individuality, their capacity for forming bonds—individually differing bonds—with
their owners the humans they share their life with.
* No other cat will ever provoke quite the same response of affection and, unfortunately, grief from the OP because she (to make a guess about the OP's sex) will never have another cat who is quite the same or who interacts with her in the same way.
In this limited sense, pets are no more fungible, no more exchangeable, than one's friends or one's siblings or one's children. And whatever the joys and fufillment that children bring to their parents' lives, there is a quiet happiness in the realization that no pet will ever become the sort of adolescent who tells Mom and Dad how they have ruined her life by being so uncool!
Pets aren't persons, of course. That's just the point. First and foremost, they don't have an immortal soul. Yet doesn't this fact make grieving over the death of a dearly loved pet all the more reasonable and understandable? After all, he or she is gone forever.
Grieve all you need to, OP. You've lost a friend, and you'll never have one exactly like him again.
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*Except in the legal sense, to speak of the "owner" of a dog or a cat is to display utter ignorance of why people have for centuries valued these animals above all others—frequently for reasons that have little or nothing to do with the "contributions" they make to a household as work animals or vermin controllers. Besides, as everyone who has ever had a cat knows, the cat owns you far more than you own him or her!