How do you keep your cool when your lesson flops?

I had them read a chapters, and then had activity stations, which my kids usually love. I tried a new method of a “silent start” where they get like 5 min to work silently before I let them talk, and that was a complete failure. I should have a them write the answers out instead of just giving them a blank sheet of paper… and they were also asked to pick a station that “was of appropriate difficulty” and that, also a fail. None of them could do the math, so it was a waste, and I realized… if they were able to do the math, they wouldn’t be in my class. I was truly flustered, so a million things happened that I truly can’t remember now. <br><br>I keep going a little, and find out that they didn’t read the chapter, and are completely lost. So they are also upset because they have no idea what they are doing. I should start over with the activity, but that would be a waste of class time, so I decide to have them read the chapter that I want them to read in class. So I get a bunch of students like “I don’t have the book…”… “I already returned it…” “I have to go grab it from my locker…” I quickly lose my cool, call a few students out, and yell a little. I finally get them to settle down, and I even have a bunch of kids who didn’t get to finish finish the activity…<br><br>The icing on the cake is that a student who has been with me for three years leaves my class in tears because she “can’t believe that I am acting like that, I am usually not like that.” <br><br>It was truly a crappy morning, and I am going a bit hard on myself. I will recover from this, and so will my kids. But… how do you truly keep your cool when things like this happen? What is your secret?