Depending on how close you were, and how able you are to find something/someone to fill the void, it's going to hurt for a long time. I found a delightful one-year-old stray with a great personality, the same color, and enough energy & affection that one would think I wouldn't long for his predecessor, who I lost around 9 months ago, but I still dearly miss Neko.
Only the exceptions can be exceptional.