The Ghosts of Beatrice Bird by Louisa Morgan

The Ghosts of Beatrice Bird is an unforgettable story of obsession, redemption, and the magic of unexpected friendship, from the acclaimed author of A Secret History of Witches.
Beatrice Bird is haunted by ghosts-a gift she's had since she was a small child. Unfortunately, it's an ability that has now grown more intense, shifting from flashes and feelings to physical manifestations she can't escape.
In a desperate attempt to find relief, Beatrice flees her home, her partner, and her psychology practice in San Francisco for a remote island with only nuns and a few cows for company. She doesn't call home. She sees as few people as she possibly can. Then she meets Anne Iredale, a timid woman who has lost everything that matters to her.

For the first time in a long time, Beatrice's gift will be called on to help someone in need. But the ghosts have taken on an even darker edge-and there is something sinister lurking in the shadows. Beatrice may not be enough to stop what's coming for them.
For more from Louisa Morgan, check out:
A Secret History of Witches
The Witch's Kind
The Age of Witches
The Great Witch of Brittany