Jisatsu Houjo

The manga centers on a string of suicides by hanging that have been plaguing the town of Kongō for the past two years, with an urban legend that a girl supposedly appears before the victims to sign a suicide contract with them, pursuing them until the victims commit suicide. Saotome, a college student of folklore studies in Kongō, has been having recurring dreams for months of himself hung by a rope in a graveyard. He begins to see a woman named Koyomi Hirasaka, a therapist who specializes in suicidal thoughts, but unbeknownst to him, he is misled into signing a suicide contract with her, and she begins to shadow him everywhere.

(Source: Anime News Network)