THEY TOLD ME "OH, IT'S JUST PERIOD CRAMPS"

Behind the bright lights of Hollywood, 19-year-old Lily Brooks O'Briant was battling chronic pain no doctor could diagnose—until reading a random Instagram post led her to the truth.

- BY LILY BROOKS O'BRIANT AS TOLD TO KATHLEEN O'NEILL

It was just another day shooting on location. I was filming an emotional scene where the car broke down when the debilitating pain hit. My cramps were so intense that I had to curl up in the fetal position between takes on the dirt road.

The crew called the medics, but I reassured them I was going to be OK-this happened a lot. I waited for the director to call “rolling,” then forced myself to stand up and deliver my lines. As my concerned castmates looked on, I thought to myself, if they only knew this is how I live my life almost every day.

IS THIS NORMAL?

I got my period when I was 13. And even from those first few menstrual cycles, I had a hunch that something wasn't right. Not only did my periods last for 10 days, but the flow was really heavy. I had awful cramps—so bad they made me feel like throwing up.

Eventually, my symptoms started happening even when I wasn't on my period. All month long, I had cramps, nausea and migraines. I lost weight because I was often in too much pain to eat.

The symptoms were so severe that I frequently had to cancel plans with friends, skip classes at school and suffer through long days on set. And then there was the anxiety—worrying about when the next wave would come and wondering if something was horribly wrong with me.