Didnt know this forum exists, so sorry for the late reply! if you enjoy three days of happiness and i had that same dream again i think you'll enjoy other Sugaru Miaki and Yoru Sumino works. Not all of their works are adapted into manga so i would recommend checking all of their light novels, they all are great. The Place You/I Called from and Itai no, Itai no, Tonde Yuke is really similar to Three Days of Happiness and At Night, I become a Monster is a really good one as well
But if what you want is manga, another Sugaru Miaki works called Parasite in Love got a great manga adaptation, i'm not really a fan on how they adapted Three Days of Happiness into a manga, i think a lot of the novel charm is how it can get philosophical for the most little thing possible and what's in the mind of Kusonoki, while i can tell they're trying their best to keep that aspect intact, its just not there yet, (also what's with the new isekaish title lol) Parasite in Love in the other hand while i have some things that i can nitpick on i think all of the novel charms are still there, the art is gorgeous and its just a beautiful story, its not as laid back as three days of happiness though. shame that it got a low score here.
There is also another adaptation of Miaki's work made by the illustrator that made Tsukigakirei and I want to eat your pancreas called Azure and Claude, its unfinished but for what have been adapted, its pretty great as well, though its not as good as Parasite in Love or even Three Days of Happiness imo.
https://anilist.co/manga/101076/Aozora-to-Kumorizora/
https://anilist.co/manga/105768/Koisuru-Kiseijuu/
