This one describes depression real good.
http://www.mangago.me/read-manga/sabishisugite_lesbian_fuzoku_ni_ikimashita_report/ (Sequel: http://www.mangago.me/read-manga/my_solo_exchange_diary/)
Realistic serie of mangas about someone dealing with depression :
1) http://www.mangago.me/read-manga/sabishisugite_lesbian_fuzoku_ni_ikimashita_report/?NznD
2) http://www.mangago.me/read-manga/my_solo_exchange_diary/ (this link is the sequel and it deals more with depression than the first manga. So maybe start with the sequel and if you don’t understand, go to the first manga)
:)
do you guys know any manga or weebtoon related to suicide, depression or anything :) hehe