Look at it in the way that "normal people! sometimes have treat weekends, sometimes they go out with friends, get hammered, eat a whole curry and then get home and raid the sweet cupboard. "Normal people" screw up all the time, but it doesn't make them gain 100lbs overnight, because one or two meals isn't going to ruin your entire diet.
Don't stress, don't be hard on yourself - trust me it'll make you feel worse about yourself, which will make you want to eat more because you feel bad (vicious circle I know!)
The good thing is that you're trying, and getting back on it.
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