You can try these~ https://www.mangago.zone/home/mangalist/842448/
https://www.mangago.zone/read-manga/mouth_to_mouse/ something something altered my brain chemistry
https://www.mangago.zone/read-manga/ashita_shinu/
https://www.mangago.zone/read-manga/kimi_no_yume_o_mite_iru/
https://www.mangago.zone/read-manga/nigatsu_no_eden/
https://www.mangago.zone/read-manga/hate_no_kouya_de_vacances_wo/
https://www.mangago.zone/read-manga/kotaete_my_drifter/ has a happy ending but it was so painful to read
https://www.mangago.zone/read-manga/yuujin_ga_yuusha/ this one was generally really calm and adorable, but the ending left a bitter aftertaste.
https://www.mangago.zone/read-manga/timeless_melody/
This is the notebook if it was gay
https://www.mangago.zone/read-manga/sangyang_the_wanderer/
POOKIE A MUST READ
just something that makes you really sad and mournful i need to feel something . Like super sad it doesnt necessarily have to include death just generally a sad depressing plot or something please