If you liked the Omae ga Sekai wo Kowashitai nara manga, the Anime-Planet community thinks you'd like:
Kazuna is a young man with a fairly normal life. He attends high school, lives with his surrogate family, and models for his somber love-interest Yaegashi's paintings. But recently, he has suffered several crippling attacks at the sight of blood - attacks which leave him incapacitated and out of control. Kazuna must now reunite with his sister who he has not seen in years, and discover the truth behind his family name and vampiric genes, before his bloodthirsty desires destroy himself, or others close to him.
The lead characters of Lament of the Lamb and Vampire Girl become vampires and it is the worst thing ever. They can't control their bodies, and feel completely helpless. Both manga also explore "replacements", creepy co-dependant relationships, and unearthing dark personal histories with a more somber mood and less action than most vampire stories.
Vampire Girl has a much more substantial plot, whereas Lament of the Lamb is pure atmosphere, and has a more interesting take on vampirism.
Chiyuki is a young girl with a terminal disease. Near death, she meets a vampire named Touya and blackmails him into spending time with her; however, he doesn't drink blood because if he took a blood partner the partner would die long before him and he doesn't want to get hurt. When Chiyuki is dying he saves her life by having her drink some of his blood, because he feels even being with her for a little longer will be enough. She returns to school and forces Touya to join her there, where they discover that one of their classmates is a werewolf who is ashamed of being a monster. Both of them slowly become closer to Chiyuki because of her warmth, her will to live, and her non-judgmental love which heals the wounds from their pasts.
Years ago, a kidnapping incident left a pair of victims with lasting psychological scars: Maa-chan is prone to violent mood swings, while Mii-kun's pathological lying shrouds his life in mystery. Now, when the news begins airing stories of kidnappings and serial murderers, Mii-kun moves into Maa-chan's house, in an effort to protect this girl who he has been through so much with. But can he save her from herself?