Core-oil, please take this from a cat lover as well whom has had our cats just suddenly die, or eventually had to be put to rest. My wife and I have found that the best way to get over our loss is to find a new one from a shelter and give it the love and attention that it so needs.
I understand that every one grieves at their own pace, but it seems to me that there just may be another cat needing your companionship.
David