Oyasumi Punpun, Sabishisugite Lesbian Fuuzoku ni Ikimashita Report Recommendations
Two stories with depressive main characters, in differents visions of the world. If you liked Sabishisugite, you should like Oyasumi Punpun as well. Trust me =)
Both are manga that deal with themes of depression, yet go off on their different ways as interesting character-driven stories. You are not guaranteed to have a good time reading through either of these, but it's a very accurate depiction of what depression does to a person. Worth your time.