Once upon a time, there was a girl who was fearless. Her mother used to have to hog-tie her to go to the doctor, because she never thought there was anything wrong with her. This girl wasn’t afraid of dirt or germs. She worked on an archaeological field crew. She had dirt under her fingernails and chewed them anyway. She ate fruit without washing it. She drank milk because it went well with cookies–not because she was counting milligrams of calcium.

Then that girl turned thirty, and woke up a hypochondriac. Was it too many pseudo-medical articles in the glossy magazines? Too many TV shows that had season finales involving brain tumors? Too many diagrams for hand-washing posted in public bathrooms at the university?

It’s possible my body is conspiring against me, planning a coup. I’m not talking about moving slower and hearing a loud crack when I climb up from the floor. I’m talking about weird quirky things–things it never occurs to you to ask your doctor about.

For example: what is this eye twitch that I suddenly have? Out of nowhere, at any random moment, my eye begins to twitch (usually when something vexing has just occurred). I wondered if it was detectable by others, and one day I happened to be standing near a mirror when I felt it. I was horrified to learn that I could actually see it twitching, convulsing in a smarmy, melodramatic wink. My first thought? Brain tumor.

And when I developed blinding, nauseating headaches while teaching college English? I crawled into bed and hid under the covers until I fell asleep, convinced it was an aneurysm, that all the paper-grading had caused the vessels in my head to explode.

There’s a fluttering that happens in my heart every once in a while. Sometimes it’s when I’m swimming laps, sometimes it’s when a good-looking guy winks at me. There was a time when I thought it was just heartache, but then my mother told me that multiple family members have ventricular fibrillation. Now my heart skips a beat and I immediately shove two fingers under my jaw to see if my pulse is racing, and I hold my breath, wondering if it will speed up, or if it will just stop.

But my worst nightmare? A tapeworm. I was convinced I had one when I was in grad school in Georgia. I’d worked at a vet’s clinic a couple of years before, and washed my hands obsessively, convinced I was doomed from being surrounded by yowling cats and dogs, certain that my body had been infiltrated. And then there was that episode of “House”–the one where the guy has a tapeworm in his brain, and they find it by doing an x-ray of his leg, because, as the good doctor says, “worms love a good thigh muscle.” And so for months I tried to think of a reason my doctor might x-ray my thigh, which is plenty healthy enough for a parasite. I still wonder about that one–it didn’t help when two of my friends confessed to once having worms, and Dr. Oz said that one in four people are host to a parasite. How much does an x-ray run, anyway?

So what happened to that gal who never thought she had anything worse than the flu? When did I start worrying about which multi-vitamin was the best bargain? Somewhere along the way, it occurred to me that life was a little more fragile than I once thought. I learned I was not impermeable to disease, that my skin and bone wasn’t the Fort Knox that I thought it was. So now I’m back to eating an apple a day, just in case the old adage was right. But you better believe I’ll wash it under warm water, and rub it a little on my jeans (because three out of four doctors say the friction does more than the water) just to be sure I’m knocking off anything that might attach itself to my thigh, my brain, or my kneecap.