Death is not sleep.
Death is the shedding of your corporal body. You lose your ability to move your body. It's like paralysis or more like stasis because everything around you seems to slow down to a crawl of time.
You only merely have to ask the people whom had heart attack or drowned and gone flatlined. What was their last thoughts. They usually think of their family or loved ones. You only merely have to listen closely to old people who are about to die tell you what they feel. They usually just feel like it's time to leave the world behind to the next generation.