It's simple. Every human being gets sick. The company can't dictate when and where. You pick up the phone, call CC and tell them 'I am unfit for duty'. They have no say in that matter. You are legitimately sick that day, doesn't matter what others are doing. Don't let this feral group of managers intimidate or bully you. The time has come to seriously reinforce your true value as an individual and professional pilot. We add value to society. Our managers only cause misery. Remember that.