欹枕无眠
[yī zhĕn wú mián]
Resting against a pillow without sleep means tossing and turning all night due to worries or excitement. It reflects either insomnia plagued by overthinking or too thrilled to settle down, which can be caused by any form of restlessness—emotional, intellectual, etc., painting a picture of an insomniac night spent pondering or dreaming with eyes open.