“You’ll be OK,” my friend Eliza said when I got my period on the evening of December 15. We were leaving for New York City that night, and I was nervous about how my cramps and mood swings would put a damper on the next day’s activities, which included a big trip to the Museum of Natural History that I’d planned with my partner, Tony, and his seven-year-old daughter, Willa.

“Probably not,” I responded as I packed the Advil and THC salve into my bag in Hudson. I knew how I could seem absolutely fine one moment, only to have an out-of-control premenstrual dysphoric disorder meltdown come on. But I was hopeful, since the PMDD episodes usually came pre-bleeding, and, though I’d experienced some major irritability, I hadn’t had what I’d call “an outburst.” Maybe I’d gotten out of December scot-free. Could I be so lucky?

The next morning, I’d woken up so excited. The four of us — Tony, Willa, Eliza, and me — ate breakfast at the Waverly Diner, which was lovely, and I was relieved at how normal I was feeling. Then, outside the diner, walking to the subway, Tony told me his way to get to the Museum of Natural History was faster than what I’d suggested. I felt the physical PMDD symptoms kick in hard and fast.

Tony describes it as a black cloak dropping over my entire body; he calls it the female Incredible Hulk. In a millisecond, my body is prickling with paranoia, pulsing with rage, heavy with sadness and anger. We walked underground and Eliza asked if I was OK as Tony walked away from me momentarily. I began crying telling her how angry I was. She looked concerned, her eyes so loving. And a little fearful, the same way Tony looks at me during PMDD, the same way I look at myself, a way that breaks my heart.

The Museum of Natural History is not the ideal venue for a PMDD episode — I already felt simultaneously disconnected from reality, while reality felt high definition, which was only exacerbated by the fossil of the Tyrannosaurus rex. I couldn’t trust myself or my emotions.

I noticed my crumpled-up ticket in the coat of my pocket. My hand was in a sweaty balled fist. It was shredded and wet. Was that a panic or anxiety attack? A rage attack? Tony tells me he knows exactly when I am in PMDD because I use the words always and never, tell him he’s an “asshole,” and text the phrase “WTF” with a bunch of exclamation points and question marks. This has happened without fail every month. We now have a deal that I am not allowed to text him swear words during PMDD week, even in acronym form. But FTS! (Fuck that shit.) Just kidding.

First up at the museum was the butterfly conservatory. I watched the metallic butterflies and could barely stand their beauty. Then we attended a 4-D movie titled Dark Universe, narrated by Neil deGrasse Tyson (who Tony says should narrate the PMDD-episode descriptions of my book). The description of the film: “Dark Universe examines the invisible dark matter underlying galaxies that, together with dark energy, accounts for that other 95 percent of the universe’s total energy and mass.”

The movie began, and there were sparkles of pink and blue falling over us. I could not retain one fact. Tony leaned over and began sternly speaking to me, because any time he reached out, I ignored him. He started saying that he knew this was PMDD energy coming at him. That it was familiar. That he wanted to have a good day with his daughter. Was I able to have a good day? Because if not, I should go my way for the day and he should go his.