How do I cope with my best work being torn down every week?

You can make a whole floor sell itself, and then every week it is stripped and reset. Pouring real skill into something so temporary wears on you. That tiredness is fair. It hurts to keep building things that are made to be undone. But the value of your work was never in how long the display stood. It was in what it did while it was up: the eyes it caught, the sales it drove, the feel it gave the place. That happened, and the reset does not erase it. The impermanence is the medium, not a verdict on the work. Start keeping a photo record of your displays. Let the images hold what the floor cannot. Seeing the body of your work in one place reminds you that it was real, even after the shelves are cleared.