If it was only one scone than you're doing great. I can't remember the exact analogy from other posts,but,this is my own. If you were building a house and had already got an architecture to plan it, paid for builders to build it. They had started on the foundations, built a whole wall and then found that one of the bricks was maybe slightly of not the correct colour but very unnoticeable. Would you scrap the whole build? Lose the money on the builders architects and other trades people? Or would you leave that one brick were it is because in the scheme of things it will barely be noticeable.
What you do today is of course important every good choice you make adds up to the sum total of a good loss every week culminating in you reaching your goal after several months or years. But, don't turn one very minor deviation to an epic redirection that sends you completely off your course.
It was one scone. It happened. Try to use it as a tool to figure out why but don't beat yourself up. You're doing really well just carry on. One meal then one day, then one week, then one month at a time. You will get there. I can't believe 2015 has gone, every day passes and I want very day to be a day that I'm getting closer to my ideal weight. You can do it. Just say it with your mouth and your brain will follow.