Hello, You seem to having constant worry and fear about being in sleep and loosing your awareness. Its a manifestation of anxiety and you need to understand a few things. Sleep is something (behavior) which all the organisms on the earth practice and infact is essential for survival. Imagine your car, suppose you switch on the ignition and keep it running, you feel feel that it should stop after some time to take rest or otherwise it will break down. Similarly if we do not switch off our ignition, then we will break down and cause ill health. Infact people die with sleep deprivation. Sleep further makes you fresh and ready for the next days work. If these thoughts are still distressing, then you should visit a psychiatrist. This problem can be a type of obsessive compulsive disorder and the ruminations have to be controlled with medications (fluvoxamine, clomipramine, fluoxetine etc.) ad with some behaviour therapy (systematic desensitization). Hope I am able to solve your concerns.