It was a chilly spring afternoon. I was shopping at Forever21 for an outfit to wear out with friends that night. While parsing through racks of clothing, I started feeling warm. Chalking the sudden discomfort up to a random hot flash, I kept shopping. But then things escalated: I started shaking; I felt dizzy, sick to my stomach. I ditched the clothes I was considering purchasing and booked it to my car. I’ll just go home, I thought. I’ll take a nap and then I’ll feel fine.

But the uneasiness kept coming back. For months, I couldn’t escape the feeling of dread that followed me everywhere. I couldn’t get through a workday without feeling like I was going to be sick. I couldn’t drive more than five minutes without needing to pull over to the side of the road, struggling for breath. I couldn’t go out to clubs and bars—even though I used to love dancing the night away—because a swarm of people enveloping me was a recipe for panic. In what seemed like the blink of an eye, I went from a carefree 20-something to someone failing to cope with an anxiety disorder.

Ironically, I was in better shape than ever when my anxiety disorder developed. I had been training for my first half-marathon, losing 20 pounds in the process. But nothing, not even the hundreds of miles I logged, could quell the endless worry.

I was constantly feeling under the weather, struggling to see a way out of the fight-or-flight pattern that my mind cycled through. I tried every naturopathic remedy to alleviate my symptoms: therapy, hypnosis, essential oils, fish oil pills, and good old-fashioned exercise.

Because I appeared healthier than ever, people didn’t realize that I was fighting the toughest battle of my life. Old classmates, coworkers, and acquaintances would stop me in the grocery store to tell me I looked amazing. Friends and family loved to compliment my new body.

When you’re suffering from an invisible illness, the body that people applaud is the very same body that you resent.

I know they were just being nice—offering kind words about the body I’d worked so hard for. But when you’re suffering from an invisible illness, the body that people applaud is the very same one that you resent. Over time, I grew bitter because the body that carried me across 13.1 grueling miles that summer was also the one that crashed and burned into an anxiety attack just minutes later. If a half-marathon’s worth of endorphins wasn’t powerful enough to unlock me from the prison of my disorder, what was?

For the millions of Americans with invisible illnesses, this internalized resentment is all too familiar. During the darkest days of my battle, there was no indication that I was ill. I stopped running because my body would burst into a full-fledged panic attack as soon as my heart rate became elevated. I could barely eat, maintaining my newfound slenderness for months despite not completing a single workout. I continued to look healthy, like the carefree and athletic person that so many people thought I was.

Only those closest to me knew how much I was suffering. One evening my grandmother called me on the phone and asked if I was OK. She’d seen a picture of me on Facebook and told me, “I know you’re smiling in the picture, but I can see pain in your eyes.” She was right.

I know you’re smiling in the picture, but I can see pain in your eyes.

I finally began to crawl out of the misery, angst, and suffering when my doctor acknowledged that, despite my best efforts to cure my anxiety sans prescriptions, it just wasn’t possible. Anxiety was biological, he explained, and I couldn’t change the way the neurotransmitters work in my brain, just as a rheumatic can’t change the arthritic pain and swelling that courses through their body. He prescribed me a selective serotonin reuptake inhibitor (commonly known as an antidepressant), and I prescribed myself the optimism to fight for a few more weeks.

It worked. Within days, my anxiety attacks became a thing of the past. Within weeks, I began laughing again. And one day, as I was heading to work, my dad smiled and told me how healthy I looked. That was a proud day.

I am still not perfect. I deal with side effects from my prescription—like hand tremors when I feel nervous and nightmares when I’m stressed—but that’s nothing in comparison to having my life back.

Last November, I left my new job crying after panicking and getting physically ill on the very first day. It was an embarrassing, frightening time of my life that consisted of spending every waking hour pleading with God, the universe, and my own body to stop letting me down. Less than a year later, I can travel, go out to bars, enjoy meals out, and be more spontaneous than ever—even moreso than before I had this disorder. I don’t know how long I’ll have to deal with anxiety; my treatment has gone well, and my physician and I have hope that I can be both medicine- and symptom-free one day soon. In the meantime, I’m just grateful to be enjoying the ride.