I sometimes have trouble sleeping. Last night I was up until 4:30. I am not completely awake, but I am 'asleep' so lightly that I might as well be awake and doing stuff.The sensation is similar to closing my eyes when someone else is driving; I'm aware of the passage of time; I just have my eyes closed.I hear the traffic going by, the cat running around, etc. I've tried getting up and doing something until I feel tired. I'll go back to bed and the same thing will happen. I can lie there, but I'm not actually sleeping. I usually fall soundly asleep just about the time the alarm is supposed to go off. It's exhausting.