Looking for the title of this book (10+ years back). A girl wakes up to what seems like her life but there are discrepancies that can't be explained. She and her boyfriend had fought the night before, but the details are hazy and he won't talk about it. She starts having deja vu and follows what she feels are clues. She recognises a man (David maybe?) but she can't figure out where she knows his face from. She approaches him and asks if she can talk to him, wanting answers.
Her boyfriend has been following her and sees her with David. I can't remember the details but it was basically history repeating itself. Turned out that what she 'forgot' about the fight was that her boyfriend had drowned her in the river in a jealous rage over seeing her with another man, the other man being David. Her boyfriend's name started with a 'C', I think. I have this feeling her name might have been Sarah or Elizabeth, but I'm probably wrong. Thank you