Vanishing acts / Jodi Picoult.

Enhanced descriptions from Syndetics:

New York Times bestselling author Jodi Picoult is widely acclaimed for her ability to tap into the hearts and minds of real people. Now she explores what happens when a young woman's past--a past she didn't even know she had--catches up to her just in time to threaten her future.

How do you recover the past when it was never yours to lose?

Delia Hopkins has led a charmed life. Raised in rural New Hampshire by her beloved, widowed father, she now has a young daughter, a handsome fiancé, and her own search-and-rescue bloodhound, which she uses to find missing persons. But as Delia plans her wedding, she is plagued by flashbacks of a life she can't recall...until a policeman knocks on her door, revealing a secret about herself that changes the world as she knows it--and threatens to jeopardize her future.

With Vanishing Acts , Jodi Picoult explores how life--as we know it--might not turn out the way we imagined; how the people we've loved and trusted can suddenly change before our very eyes; how the memory we thought had vanished could return as a threat. Once again, Picoult handles an astonishing and timely topic with understanding, insight, and compassion.