Love Comedy Manga ni Haitteshimatta node, Oshi no Make Heroine wo Zenryoku de Shiawase ni Suru (Light Novel)

I was hit by a truck one day, and when I came to, I found I had become the best friend of the main character of a romantic comedy manga. Ah, this has gotta be a dream, right? But then, the lesser-known heroine Sei Shimada appears before me. I'm a big fan of hers, so I convey my love for her with a simple "I love you." I'm completely satisfied now that I've done so, but why am I not waking up from the dream...?!