Leo
Rather than love, than money, than fame, give me truth. I sat at a table where were rich food and wine in abundance, and obsequious attendance, but sincerity and truth were not; and I went away hungry from the inhospitable board.
Henry David Thoreau
You have been quietly maintaining something that would fall apart without your attention, and the interesting part is how much you enjoy the maintenance itself. The task that nobody officially gave you has become the task that nobody else could do as well, which means it has become yours in the way that matters more than paperwork. There is a particular satisfaction in being the one who notices what needs noticing, who steps in before the stepping-in becomes obvious. The responsibility chose you because you were already doing it.