[Rhys feels bad about everything he's leaving out, his mixed bloodline and the real source of his magical abilities, but he's also coping with the fallout of having his biggest secret pulled out of him. He needs time before he can come clean.]

That's what Incubi do. They steal life force. You can heal it back, but it takes a lot of care. Good food, plenty of sleep, some fresh air and sunshine if you're up to it. Mostly being gentle with yourself so your spirit can replenish itself.