How do I protect my business from the big shocks that threaten everything?

You can weather most setbacks now, which means you have built real resilience. What still frightens you are the big shocks, the ones large enough to threaten the whole thing at once. That fear is not weakness. It is accurate. Some blows are genuinely serious, and pretending otherwise would leave you less prepared, not more. You cannot make your business shock-proof; no one can predict every blow. But you can make it shock-resistant, and those are different aims. Resistance comes from margin: reserves you do not need on a normal day, more than one source of income, relationships you can lean on, a plan for the failure you most fear. You build these in the calm precisely so they are there in the storm. Pick the single shock that would hurt you most and spend an hour this week just planning for it, on paper, before it happens. Not to invite it, but so that if it comes, you are deciding from preparation instead of panic. A shock you have imagined is far less able to threaten everything.