You'll feel like indulging a bit today and that's OK as long as you also do something to counteract your indulgence of choice. If it's ice cream, for example, understand that lactose is difficult to break down and it also causes mucous build-up, so drink an extra lot of water to counteract these effects. If it's taking a break from exercise, make today the day that you get to bed early so you are refreshed for tomorrow.