We Shadows (Night's Dream, #1)

After a year of mourning a dead boyfriend, Shane Valentine wants a quiet first year at college. Instead, someone brutally stabs her.
Surprisingly, Shane wakes unharmed with memories of her murder and a significant problem: no one seems to know she exists. That is no one except her roommate, an accomplice to her murderer, and several supernatural creatures — whom she is startled to discover both exist and would prefer that she didn't. Their wish might be granted soon if she cannot find out who killed her, why, and how to stop the world from erasing her entirely.
On her side are an imperious daemon, a confused ghost, a dealer in drugs and memories, a Goth witch, and a nebbish occultist. Against her are the children of the gods, a shadowy cabal, and the totality of reality itself.