Heartstone by Lynda K. Scott

Eric d’Ebrur is out of time. He must find the legendary Heartstone and fulfill the ancient Gar’Ja bond he shares with the Stonebearer. But when he finds her, he discovers that love can be more dangerous than the Gawan threat. Eric can defeat the mind-controlling Gawan but will it cost him the woman he loves?
After terrifying episodes of hypersensitivity, Keriam Norton thinks she’s losing her mind. When handsome shapeshifter Eric d’Ebrur saves her from the monstrous Gawan, she’s sure of it. But insane or not, she’ll find the Heartstone and, if she’s lucky, a love to last a lifetime.