What you’re experiencing is the “let down effect” or post-stress illness. Dr Marc Schoen is a psychologist who first identified the “let down effect”. During a stressful period our body releases stress hormones called cortisol, adrenaline and noradrenaline. These hormones activate our immune system to fight against illness during that time. Who really wants to be sneezing their way through an important phase of your career or family life? What happens is our white blood cells are like soldiers patrolling the gates and stopping opportunistic infections taking us down.