The day after I donned my gown and tossed my cap last May, I woke up with a dull throbbing in my left big toe. I stretched it out and wiggled it around and tried to push the thought of it as far back as it would go.

You're too old for this, I thought. Stop it.

The harder I tried to push it away, though, the stronger the thought of that dull, menacing throb kept creeping back up -- intruding into a conversation with a friend, stopping me in my tracks at Duane Reade.

Stop. Stop. Stop.

I took deep breaths and counted to ten and tried to distract myself until finally the urge propelled me to my computer and onto WebMD.

Symptoms: Numbness. Tingling. Slight swelling.

A blood clot.

Within seconds, I was crying and grasping for breath on the floor. It had probably already spread to my heart and lungs by now. I had hours to live, hours until I went brain dead. How cruelly ironic that it should happen the day after graduation.

The gaiety, the accomplishment, of yesterday seemed forever ago.

Hypochondria, you see, is like a dementor -- those soul-sucking creatures from the Harry Potter books. It sucks not my soul, but every ounce of rationality, every ounce of sanity out of me, leaving only sheer panic. It takes my self-respect with it too. What kind of 23-year-old is reduced to hysteria by a minor ache?

In an attempt to reconcile the woman I am with these infantile episodes -- and as a devotee of the religion of analyzing everything and anything -- I've tried to find the root of my hypochondria. I've always been anxious, a worrier and prone to panic attacks, but there is something particularly relentless and all-consuming about my thoughts on health. There was the time in middle school when I left to go to my pediatrician midday, absolutely sure a pimple behind my ear was cancer. Several times in high school my parents banned me from getting an MRI. There was also the time, not too long ago, that I went to my OB-GYN convinced I had cervical cancer. When I was told my cervix looked just fine, I asked her to please look at a freckle on my hand.

For a while I thought it was my dad's influence. The man sends family-wide BEWARE emails when China reports a single case of the avian flu, taught us to always sit in the back of a movie theater (if someone sneezes, the sneeze travels forward) and to steer clear of buffets (just think of all those germ-covered hands).

Now I think it's just my own fear.

Fear manifests itself in a million ways. For many of us it latches onto something we can't control -- the future, financial insecurity, heartbreak, the death of a loved one -- and what is less controllable than illness?

Here's what I've learned: You can't out-rationalize fear. Don't even try. The only thing that has ever worked to calm me down in these moments of panic is to have a little faith. Faith that things will be okay and that if they're not -- if one day that throbbing in my toe does turn out to be a blood clot -- that I will have the tools, the strength and the courage to face it.