Being Dead (The First Year). Marble Grant

Superhero Marble Grant dies suddenly on a blind date, a bullet between her eyes. Maybe the worst ending of a blind date in recorded history. But instead of taking the white light to the next world, she finds herself still here. Her first year as a ghost agent begins with her sitting on a dumpster in a dirty alley watching the man who killed her and her date. The entire first year got stranger from there.
And over that year Marble Grant and her lover, Sims, saved a lot of lives.