A thermometer sits on the window sill of my bathroom, right next to the toilet, so every time I go to the bathroom, I can take my temperature. I’ve been feeling like I have a low grade fever for weeks, and these days, a fever isn’t just a fever. It’s a signal you may have the corona­virus. And so I take my temperature about eight times a day to see if my fever has risen.

This virus has come at an inconvenient time, revving up my usual hypochondria. I always think I’m dying: Mosquito bites are tumors. Pimples are lesions. Sore throats are the early stages of throat cancer.

My fear was likely fueled by a medical drama from childhood, when a camping trip at age 11 turned into walking pneumonia, and after a few trips to the pediatrician, I was told I needed open-heart surgery.

I’m now 56, and yet memories from that week in the hospital remain vivid: watching the TV series “Medical Center” the night before my surgery, having a crush on the intern who resembled John Denver and took my blood, and how he missed my vein one morning, and I bled on my frilly blue-and-white bathrobe.

I remember the prickly black stitches that went from under my arm to the middle of my chest after my heart surgery, right under where I would later have breasts, and that I had a roommate named Stacy, who was there before my surgery and then gone when I returned to my room.

But one of the most uncomfortable memories was just after my surgery.

As I lay in an oxygen tent in the intensive care unit, I had a drainage tube connected to my lungs. The tube was inserted into my chest through a small hole in the side of my body near my ribs to drain any fluid that built up after surgery. Even under anesthesia, I was disturbed by the idea that something could be both inside my body and outside of it at the same time, like a piece of spaghetti that makes its way down your throat and into your stomach and yet part of it might still be in your mouth. Some things shouldn’t be in two places at once.

According to the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders, it appears I have what’s called health anxiety disorder.

It has been a yeoman’s task these days to keep my fears at bay, as I tell myself my thoughts of dying are silly, irrational, the product of paranoia, when there’s a new figure every day of how many people died the day before. Were they, too, trying to write their fears off as irrational, before everything went south? I try to consider the odds that I will die of this, which are slim. But I used to think, what are the chances that my mosquito bite is cancer? And then my 62-year-old father got esophageal cancer, an illness that seemed to come out of nowhere, which presented itself on the outside as a bunch of bumps that resembled bug bites. He was dead in just 10 months.

But what my father’s death did to me, in terms of fueling my paranoia, my son’s birth has helped undo. Now 9, my son has moved through germ infested classrooms filled with mucous-covered toys, bringing home every illness on a pediatrician’s greatest hits — flu, strep, stomach virus, even coxsackievirus — and not only have I caught them but he has, too. The psychological benefit of that is, when I have a fever, my son has a fever, and I can see it’s not fatal. When I have a cough, my son has that cough, making it clear it’s not tuberculosis but a cold. He’s like a canary in the coal mine, except a good one that provides proof over and over again that the coal mine is safe.

But this coronavirus is putting my methods to the test. Tonight, as a sore throat rolled in and my eyes felt glassy, my mind seized on the idea that I had the virus, and I started to feel short of breath — no doubt from anxiety. I skipped an online writing class because I didn’t feel up to it. I felt a low grade fever.

I had taken my temperature this morning — nothing — and, after dinner, I took it again. 96.9. Normal. I walked over to the mirror and my face looked pale. My eyes looked glassy, and there were black circles under them. I looked sick. Aside from being almost 60, I had no underlying health problems. And then I remembered how much I used to smoke. I quit 16 years ago, but I’m sure the damage is there. I know what the filters on my stove vent look like, after a year. My lungs can’t look much better.

And then there’s the cancer, I thought. They say having had cancer can be a complicating factor. But then I remembered it wasn’t I who’d had cancer. It was my father, and my husband, who was successfully treated for Hodgkin lymphoma — both years ago. I was getting confused.

The coronavirus also plays on one of my greatest fears: death by asphyxiation. The thought that if I got it, I wouldn’t be able to breathe is just, well, suffocating. I’ve been reading my son, “20,000 Leagues Under the Sea,” and we read a chapter yesterday in which the ship, the Nautilus, gets lodged underneath some icebergs and can’t break free.

Several members of the crew leave the ship to chip away at the ice, but they had to get through several feet, and their air supply is dwindling. They chip away at the ice all day but the next morning, it is even thicker, and their air reserves are dwindling. As the air on board the ship becomes more difficult to breathe, the men on board get dizzy and weak, and their lips were turning blue.

As soon as I closed the book, I went into the bathroom and took my temperature again: 96.9.

I went for a run not long ago, and when I returned, my son said he’d thrown up. It was just a little, he said, so I gave him a glass of water and told him to start his school work. I made him a bowl of oatmeal, hoping the weighty cold weather remedy would keep things down. But at about noon, he went to the bathroom, and as he was washing his hands afterward, he threw up in the sink. He threw up again later that afternoon and spent the rest of the day lying on the couch. When I looked at him later, he looked gray. The canary was ill.

The next day, I told a friend about his sickness, and she said, “It’s not the coronavirus. He has a stomach bug!” It was the same thing his pediatrician said when I had called.

When my son woke up the next morning, he had his color back and the first thing he said was, “I’m hungry!” We were saved once again.

The medical roller coaster in my head will continue to go up and down in this period, but as the ride enters a dark scary tunnel, I need only watch my son, who is often sitting in the first car, bright eyed and smiling, and already emerging into the light.