it's about a teenager trying to survive a frozen wasteland while carrying the corpse of his friend, a little girl he also found in the wasteland but failed to survive the plague. the girl was alive at the start of the story and have him a notebook to write on his journey and he ended up using her book after she died too.
Basically, it's a childhood friends turned lovers smut.
ML has short black hair with a pretty girlish face and the FL is sorta tomboyish and they've been friends since they were young. Currently in high school, the FL sees him as just a friend (he DEFINITELY doesn't) and they're close enough to even have sleepovers with each other like girl pals. Then I think there was somnophilia??? ML hella shady and pretty yandere ish. Idk man I'm just trying to find this manga ok. The title is two words long.

Please find this: The manwha it starts off with the seme being a short goofy nerd kid (black hair) and the uke (brown hair) is some double faced asshole with some deep issues. the seme then suddenly has a growth spurt and is now like super hot and tall. the two of them then became like a situationship and then got separated cuz of the uke's other issues. I dropped it out of frustration cuz I read that the uke then loses his first time to someone other than the seme but now I'm curious how the story is rn
https://www.mangago.me/read-manga/monochrome_diary/ i think it's this, it ragebaited me so bad i dropped it + picked it up again 5 times
also it's completed now, the ending itself isn't "bad" i would say, but it's still unsatisfying like the 2nd half
oh my god thank you so much. also ur so right I hate the story and the characters are all wi,py as hell but I'm still morbidly curious