When I started my company 20 years ago, I was driven to succeed. (Some might say obsessed.) For years, I defined myself by my successes, my clients and my projects. I worked long hours and rarely a weekend went by without coming into the office.

Then about seven years ago, I found myself staring at the ceiling every night wondering, "Is this all there is? Does my work have purpose? Was I really put on this earth to entertain 1000 beer salesmen at their annual meeting?"

When the universe reaches down and taps you on the shoulder, you begin to question the very foundation on which you've built your life. And that can be a frightening, painful experience.

I needed a drastic shake-up in my life to answer the hundreds of questions churning inside my head. I decided to take a two-week, silent walk across the Sahara desert. I had never engaged in self-reflection at that level, had never been that quiet with myself before.

Over the course of the two weeks in the desert, I began to see clearly my mind's ability to determine the future. I saw, for the first time, how capable we are of creating, or sabotaging, our own happiness.

Lillian's story demonstrates this best. Lillian was my roommate at the hotel in Marrakech as we prepared for our desert journey. I'll never forget the night before we were to enter the desert -- Lillian was charmingly neurotic as she darted around the room, zipping and unzipping duffel bags, back packs and her money belt.

She dressed like a gypsy, having borrowed clothes from friends and daughters, I assumed because Gucci didn't carry a line of desert wear. A consummate New Yorker, Lillian had never slept outdoors in her life. (At least I had been a Girl Scout.)

I worried about Lillian as we headed into what was to be a pretty rough environment for two weeks. As it turned out, I needn't have bothered-she turned out to be a delightful and delighted traveler. Even when the temperature plummeted to unexpected lows and we awoke with frost on our pillows -- something our Berber guides had never seen -- Lillian seemed enraptured with the experience.

After dinner on the fourth day, when we broke silence to share experiences, Lillian told us a story.

That day we had made camp early at the foot of several rocky dunes, the cold weather having slowed us down. Taking advantage of the late afternoon light, everyone scattered to various journeling or meditation spots to relax.

Lillian had climbed to the top of one of the large dunes and was enamored with the endless sight before her. "I was at the height of my bliss," she told us. "Totally happy and filled with peace."

And then, a thought struck her. "I wondered where my wallet was," she said. "I had no idea where the thought came from, but it compelled me to open my back pack and dig for it."

When she opened her billfold, her heart sank when she saw that $500 was missing. She admitted that she had always had big money hang-ups, so the loss of the cash was devastating for her. She scrambled down the mountain, trying not to jump to the conclusion that one of our poor Berber guides, to whom we entrusted our bags every day, had stolen the money.

After involving Tracy, the trip manager, and retracing her steps several times, Lillian was in a frantic state. Tracy tried to calm her down. "Just look in your money belt one last time," Tracy suggested. Lillian had searched it five times already, but she unzipped the belt and looked.

The $500 was there.

"It was a miracle," Lillian later told us with tears in her eyes as we sat around the campfire. "Not that the money appeared, of course -- it was there all along. What was miraculous was this: for the first time in my life, I was able to see my ability to sabotage my own bliss."

What had planted the thought about the wallet in her head just as she was at the height of her ecstasy? What enabled her to invent -- actually invent -- an alternate reality that caused her to frantically interrupt the serenity she felt? How cleverly her mind worked to choose her greatest hang-up -- the loss of money-to interject a dose of distress into an otherwise perfect moment.

When I heard Lillian's story, the cobwebs started clearing in my head. If Lillian can create such a distressful reality with one thought, I wondered, what's to keep me from creating a positive one?

That trip became a pivotal moment in my life. Rather than feeling trapped in my business, I began to make changes that allowed me more freedom and created more meaning in my life. I began whittling away at the negative thoughts that limited my growth and kept me bound to my fears.

I'm not always successful at this. Every once in awhile I find my mind working up an imaginary conflict where none exists -- and before I know it I look back and see that I've managed to sabotage my happiness, at least temporarily, again.

We determine our future every minute of every day. With every thought, we create our own reality -- one that can either lift us up or take us down. Next time you're in turmoil, try to remind yourself that it's all in your head.

I recently shared this story with a woman’s group at the Mecklenburg County jail. In the group were women with charges ranging from DUI to homicide. I was amazed at the power and insight they displayed. At the end of my talk, Dianne Moore, the group's leader, asked the women what they learned. A 16-year-old girl named Paris raised her hand. "I learned that it’s great to be dedicated to your work. But if you're not dedicated to your life, you'll never be happy." Well said, Paris. Well said