(FORTUNE Small Business) – The way I remember it, I had just finished an early-afternoon meeting when something--everything--changed. I returned to my office and sat down in my chair, and suddenly, inexplicably, began to shake. Tears streamed next. Then I was hyperventilating. And so the cycle continued for more than 45 minutes. Exhausted by the ordeal, I spent the next day in bed, only to have the terror strike again 24 hours later while I was driving through San Francisco. My doctor soon slapped a label on my condition: I was suffering from panic attacks.

I missed work for the next three weeks and then came back only part-time, unable to resume my usual ten- to 12-hour-a-day regimen. As it turned out, the attacks were the symptoms of a withdrawal from medication I had been taking for months following some minor surgery that had left me in pain. When I decided earlier this year that I didn't need the painkillers anymore, I chucked them and inadvertently found myself coming as close to insanity as I ever will. I hope.

Our family-owned plastic-bag-manufacturing company wasn't prepared to have its chief executive disappear for almost a month. Certainly my brother and sister did everything they could to cover in my absence. My sister answered e-mails and returned calls, and my brother took over my pricing responsibilities. Other staffers took on my purchasing duties. But as each week passed and I either didn't come in or was barely able to function, the work piled up. A large bid, a complicated price sheet, a difficult contract negotiation, all floundered. Not because there weren't people capable of doing them, but because no one knew what needed to be done. I hadn't told them about any of it.

Like many small businesses, our company had no backup plan for the possibility that its chief executive might be incapacitated. As a result I worked on projects that no one knew about, and not one person in our company had a chance of figuring out what they were. Perhaps someone could have asked customers directly if they were expecting something from me, but that might have raised questions about where I had gone. And no one left behind had any idea what to say about my condition.

By the time I returned to full duty, several of my customers were in full revolt. One figured I simply hadn't returned calls because I didn't care. The company threatened to yank its business. Another longtime customer began to spread gossip about my health, insinuating that I had suffered a nervous breakdown. That person spread the word to several of my other customers.

Today, back at full speed, I recognize a couple of key lessons. I know now that the business goes on whether I--or any other senior manager--am there or not. So I am making it a point in our weekly management meetings for each of us to list projects we're working on so that someone else can take over if necessary. I've also concluded that too many duties are concentrated in my hands, and I am trying to delegate more. I've shifted customer-account responsibilities to my brother, hired a sales manager to shoulder some of the workload, and finally consented to employing an assistant. At the very least, that person will know everything that I am working on.

But ultimately, total transparency is my aim. Just as shareholders of a public company would need to know what had happened to a chief executive who disappeared for weeks, our customers had a right to know that a reaction to medication had flattened me--and to get a timetable for my return. I'm not sure that the approach we took cost us orders, but it certainly didn't do my reputation any good. And as far as I know, there's no pill that can restore that.