My Kat has night terrors too and Needs a night light on. If she wakes at night without one, she screams blue murder and is terrible to try to resettle. She's fine with a nightlight on. She started this about a year ago. She'd wake up screaming and then she'd cling to us when we went to calm her down. We worked out she was having bad dreams and she'd not want to go back to bed. I found that after a few weeks of her waking and us going in and cuddling her and giving her some time to get over it and then putting her back to bed and telling her we were right next door etc, she started to know we were there and the fear slowly left her a bit. The nightlight def helped too. Now she only does it if her room is completely dark when she wakes. Once again, 30mins of cuddles and kisses away from her room and she seems to go back to bed ok as long as she knows were are near and will come to her rescue if she needs it..