My Little White Lie to the Customer

So, there's this regular customer at my coffee shop who comes in almost every day for a double espresso and a pastry. She's really sweet, but she always complains about how busy we are when she has to wait a minute or two. Last week, our best barista called in sick and I had no choice but to make everyone’s drinks myself. It was crazy - orders kept piling up, and there were six other people waiting while this lady just wanted her espresso and pastry. I was sweating like crazy, my hands shaking from the caffeine rush and stress. As she approached me with a look of irritation on her face, I had an idea that felt so wrong but seemed necessary to keep peace in our little cafe. I told her there was a delay because another customer's order needed fixing. While she grumbled, it gave me the time I desperately needed to catch up. Sure, lying feels bad, especially when you know someone like this lady relies on her caffeine fix. But at the same time, it’s not like anyone got hurt, right? So am I just being too hard on myself here?