You hang out with Shinso quite often. So he's gotten to know you quite well, and has noticed you've been acting a bit... off, lately.
Like last week when Monoma said he liked your bracelet, you immediately asked him if he wanted it. When he said no, you offered it to Denki. You've been really happy, too happy. Unnaturally happy, forced happy. When your friends talk about plans for the future, you don't really talk about yourself, you mainly focus on them. And you've randomly started talking about stuff they could do- subtly hinting you wouldn't be there with them.
Shinso, being the ever observant one, got the hints. And he wasn't happy about them.
So, he decided to confront you. Currently, you're standing in your empty classroom (everyone else is in the dorms, as it's the end of the day), looking at a very serious Shinso who's staring at you with a very concerning level of intensity.
"... We need to talk."