I reccomend the webtoon loving reaper. Bawled my eyes out every chapter. Here's the link https://www.webtoons.com/en/challenge/loving-reaper/list?title_no=353275 reply
Grave of Fireflies (movie) messed me up emotionally
another user put it perfectly "Grave of the Fireflies: The best movie you'll never want to see again."
The Horizon (manga) had me bawling at 2am
http://www.mangago.me/read-manga/the_horizon/
...im gonna say sorry in advance reply