Lee -
My condolences and sympathy, there are no words that can ease the great sense of loss. The house will seem a lonely place for some time, but soon enough the warm memories will replace the hurt that you're now feeling.
Our very old long stripe tabby left us last year, she was mature when she came to us, found abandoned and meowing at the door of a friends apartment. She was not able to keep her or she would have, so she told us a sweet little kitty, (she certainly was,) needed a home and she became ours for nineteen great years. She did well until the last day, then she let us know she didn't feel well, our vet said the internals were shutting down, to let her go on would be only misery for her. An easy call for us, time for a good sleep, no more hurt.
We lost our two old lab's one year apart, Maggie at 17, Lucy at 14. Luckily we found a black lab litter was ready, we brought 9 week old Ellie home ten days after Lucy passed, a ball of fur and energy, the house seemed a pleasant place to be again. Ellie was born on Christmas day, four years ago this year, had we been thinking, Holly would have been an appropriate name.
So, Lee, somewhere there is a nice kitty that needs a good home, you have that home and you sure need another kitty. Milo would be pleased if you were not so unhappy.
Best regards
Patrick