The Roman emperor Marcus Aurelius Antoninus was the last famous Stoic philosopher of antiquity. During the last 14 years of his life, he faced one of the worst plagues in European history. The Antonine Plague, named after him, was probably caused by a strain of the smallpox virus. It's estimated to have killed up to 5 million people, possibly including Marcus himself.
In the middle of this plague, Marcus wrote a book, known as The Meditations, which records the moral and psychological advice he gave himself at this time. He frequently applies Stoic philosophy to the challenges of coping with pain, illness, anxiety, and loss. It's no stretch of the imagination to view The Meditations as a manual for developing precisely the mental resilience skills required to cope with a pandemic.
First of all, because Stoics believe that our true good resides in our character and actions, they would frequently remind themselves to distinguish between what's "up to us" and what isn't.
Marcus likes to ask himself, "What virtue has nature given me to deal with this situation?" That naturally leads to the question: "How do other people cope with similar challenges?" Stoics reflect on character strengths such as wisdom, patience, and self-discipline, which potentially make them more resilient in the face of adversity. They try to exemplify these virtues and bring them to bear on the challenges they face in daily life, during a crisis like the pandemic. They learn from how other people cope.
In fact, of all the things in the world, we can only directly control what we do, think, choose, desire, and fear.
Everything else, including everything our society tells us that we need to "get a life" - riches, property, fame, promotions - depends on others and on fortune. It is here today and gone tomorrow, and it is usually distributed unfairly.
So to pin our dreams on achieving such things makes our happiness and peace of mind a highly uncertain prospect.
The Stoics propose that what they call "virtue" is the only good. And this virtue consists above all in knowing how best to respond to the things that befall us, rather than fretting about things we cannot control.
For Marcus, all those "goods" that markets trade, and our contemporary advertisements hawk, are "indifferent". It is what you do with the pleasurable things, and with the difficulties you face, that shapes how happy or unhappy you will be.
It is almost as if Stoicism asks of us a kind of "virtual lockdown", anticipating the actual one some of us are currently experiencing. The inability to go swimming, or to the football, gym, or movies, is for the Stoic regrettable. But it isn't devastating. For s/he has weighed such preferable external things at their relative value.
This is the Stoic "good news". Pandemics, bullies, and mischances really can rob us of our money, our jobs, our reputations. If they are malign enough, they affect our physical health. But they cannot change our minds. They cannot make us commit evil actions. They are powerless to even compel us to think resentful or hateful things about our fellows.
If what your insulter has said is true, then change. If what they have said is false, it does not merit your being upset by it. If they have betrayed your trust, the shame and the fault lies with them.