Can someone reccomend me very sad and heart breaking mangas (not yaoi)

http://www.mangago.zone/read-manga/koizora/
this one is so fucking sad ┗( T﹏T )┛

http://www.mangago.zone/read-manga/transparent_cohabitation/

not a manga but a webtoon. DIAMOND DUST!!
search for it. it's lovely.

http://www.mangago.zone/read-manga/can_t_see_can_t_hear_but_love/

Orange Marmalade