My Client Thinks I'm Perfect When I Really Blow My Deadlines

I work from home as a freelance graphic designer. Last year, my client, Sarah, came to me with an urgent project for her startup company's rebranding. She needed some fresh logo ideas and brand guidelines within a week, but the tight deadline wasn't really my fault; she only contacted me late on a Friday afternoon when I had no work planned in my calendar until the following Monday. I sent over some initial concepts quickly to show how responsive I am to her last-minute requests. She loved them so much that she wanted to meet face-to-face as soon as possible for feedback and adjustments, which was inconvenient because we live on opposite sides of town and I have limited free time outside my work hours. After a series of delays due to our conflicting schedules, we finally met three days later. By then, the project had become so important that I ended up spending way more time than initially planned working through it with her in person rather than back-and-forth emails or chats. This led to me being way behind on my usual workload and having to shuffle deadlines for other clients to accommodate this startup client's urgent requests. Despite all the overtime, Sarah keeps praising how efficient I am and is eager to work together again soon for more projects. I feel like a total hypocrite because she has no idea that her single project has become a real headache compared to my normal workload. But I also don't want to lose such an important client and risk losing out on future opportunities with them just to tell the truth about how busy this made me, even if it's not entirely fair. Am I the asshole for taking advantage of her unrealistic deadlines and pretending everything is fine? Or am I doing good business by keeping a customer happy and maintaining positive working relations? What would you do in my situation?