Not Quite Dead Yet by Holly Jackson
Jet Mason is 27 years old and waiting for life to begin. Unfortunately for her, on Hallween night, someone breaks into her family's home and hits her in the head with a hammer, which causes an aneurysm that is going to kill her, probably in about a week. So she decides this is her last chance to do something--namely, find her murderer. With the help of her best childhood friend, Billy, she starts working the clues and uncovers a lot of long-held secrets. Will Jet find her killer while there's still time left? It's a gripping story that keeps you on the edge of your seat till the very end.