Source : Webster's Revised Unabridged Dictionary (1913)

Sleepless \Sleep"less\, a.
   1. Having no sleep; wakeful.

   2. Having no rest; perpetually agitated. ``Biscay's sleepless
      bay.'' --Byron. -- {Sleep"less*ly}, adv. --
      {Sleep"less*ness}, n.

Source : WordNet®

sleeplessly
     adv : without sleep; in a sleepless manner; "he was lying in bed
           sleeplessly"