So how to deal with defeat?

I had a Teachers' Group meeting so I couldn't make it to practice until about 830, and even that required a hard run from SoHo to TriBeCa fully loaded. Well, not with bogu, but with enough to leave me sopping. Not as exhausted as the poor kohai whom Sensei decided to shove into bogu without even an apprenticeship in do and tare, but still tired. So it was starnge to try and get right into mawari-geiko still not warmed-up enough. But the point is that I lost in shiaigeiko with kote to another mudansha who hadn't been around in a while.

And so now is the question: how do I deal with this loss after entering the match with such I'll-manage-and-control-this confidence? It's easy to chalk it up to my having missed the real practice. Or the offtiming of someone who hasn't been around, which is harder to read. But it's probably better not to look backward so much--to just strike more fully committed, and not to be tempted into thinking that I am good enough to win without throwing myself fully into the match. Or something. But no second-chances in shiai.