Ghost in the Blue Dress by R A Slone

Fifteen-year-old Jenna Moores is struggling with her father’s recent death. Not long after his passing, a ghost from her childhood returns. When she was young, Jenna’s father convinced her that the ghost was just her imagination and that he would always protect her. But now he’s gone, the ghost is back, and Jenna knows she’s not imagining it. As the entity grows stronger, its threats move from alienating Jenna from her friends and family to killing her. Alone and afraid, she must find and destroy the link that holds the spirit to this world…before Jenna, too, becomes a ghost.