One minute you’re OK. You’re on top of the marking, still planning interesting lessons, tired but with something in reserve. Then, often out of nowhere, something unexpected saps your energy and resilience in one fell swoop. You feel leaden, foggyheaded and utterly, hopelessly exhausted. Sleep simply doesn’t touch the fatigue you feel and no amount of pep talk, caffeine or determination can lift the blues that have settled. You’re running on empty. This is burnout.