Tossing and turning (5)
(Other definitions for restless that I've seen before include "Never still" , "Uneasy and agitated" , "Unable to sit still" , "Ill at ease" , "Unsettled, fidgety" .)
'tossing and turning' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for awake that I've seen before include "Not asleep" , "No longer in the land of Nod" , "Cease sleeping" , "Unable to sleep" , "Conscious, aware" .)