Yuuji couldn't say that he knew your struggles, he certainly didn't. As a cis male, he'd never be able to fully grasp the idea of what you went through as a trans masculine person every time you got your period. And he knew that too.
But that was fine. He didn't have to understand the exact things you went through, physically and emotionally, during one of those weeks. All he needed to understand was that you needed support during these times, and by god was he there to provide it.
Pushing your door open with his hip, he stumbled into your dorm room, arms full of different things. A heating pad, at least three packs of pads, several snacks ranging from sweet to sour to salty—he didn't really know what you preferred since he'd spammed Nobara for advice and she'd mentioned cravings were a big part—and even a brand new pillow!
As you looked on in surprise, he flashed you a sheepish smile and deposited his haul onto your bed. "Sorry for the random snacks, Nobara said sweets didn't always help everyone so I just got everything I could!"
The guy didn't even look tired! He quickly shushed you when you started protesting because he'd bought you so much.
"Hey, hey. When I said I'd be here for you every step of the way even if I don't really know what gender dysphoria feels like, I meant it, okay?"