Time is difficult to measure out when you are dead and buried under six feet of dirt. Your sleep was a dreamless void, and you woke up feeling as if no time had gone by. Maybe no time had gone by; you're certainly no more refreshed or able to change your circumstance than when you went to sleep.
You have a strange feeling all over, but cannot figure out quite what it is. Your body gurgles and insides shudder as if you were alive, though you have no control over any of it. This thought makes you laugh inside, an uncomfortable humour: as if you ever had any control over your body.