Sorry to hear that man. We lost 2 of our cats over the past 2 years or so, 23 and 22 respectively. Both were showing their age but I'm pretty sure the second lost his will after the first passed, he lasted almost a year but just wasn't the same, they did everything together for many years and he never really knew a life without her, she really mothered him as her own when my wife first brought him home.
My oldest dog turned 10 last October and is really showing his age this year, not looking forward to his day coming at all. Our other dog and one remaining cat are both 5 so they are just in their prime.