As a fellow anxious girl I kind of get why she doesn't want to make him worry BUT here's the thing: it doesn't work. You'll only make things worse and your relationship will suffer badly. From my personal experience, at least.
I sure hope Riri wins and Misaki finally disappears. I didn't dislike her this much before, but the more the story goes on the more she's just annoying.
It's okay to keep the mystery up but damn...