Eleanor Oliphant is Completely Fine by Gail Honeyman
Eleanor Oliphant is NOT completely fine.
That much is clear from Chapter 1. Eleanor works a drudge job as an office assistant, a job she excels at, but is paid a pittance for. She survives on frozen meals and vodka (lots of vodka), and her weekly phone conversations with Mummy. Her dark and tragic past stays in the past, where it belongs. But Eleanor's tightly controlled life begins to spiral horribly out of control when she falls hard for a mysterious musician who doesn't even know she exists. As she struggles to keep an even keel, repressed memories from her childhood begin come back, and the darkness takes hold.
For a book that has cropped up on several "Feel Good" book lists this, Eleanor Oliphant is seriously dark and pulsating with grief and repressed memories. For fans of unreliable narrators, and anyone who loved The Rosie Project but thought it was too perfect.