Liane Moriarty: What Alice Forgot

The main character, Alice hits her head while exercising is  the gym. This results in memory loss, and despite the fact that she approaches her 40th birthday, she believes she is 29 and pregnant with her first child. She can't remember anything from the last 10 years, and doesn't understand what has happened with her relations to her husband and sister. She has changed from  a loving, relaxed messy person into a supermom. The story about her memory loss is well told, but I was struggling to be convinced that her personality could have changed so much in 10 years time.
In addition to Alice, we also hear about Elisabeth, (her sister) and her struggle to become mom.
Even though the book has been on the New York Times bestseller list, I didn't find it  completely convincing.
By Liane Moriarty I have also read: The Husband's Secret - I think it was better.