Is my brain not supposed to be at rest when am asleep?

My brain still functions fully when am asleep? Recently when am asleep I feel my brain working,processing information,show different images,even playing strange movies and dramas and dialogues when am asleep. I just feel it that my brain is restless and not resting when i sleep and thus i sleep a restless sleep and wake up with slight fatigue,headache and a saturated head. I dont have migraine neither is my blood pressure high.what is responsible for this and how do i stop it ? I just want my brain to rest while am sleeping and to have a peaceful sleep like ever b4