Sri Aurobindo
Bases of Yoga
Bases of Yoga
The consciousness in the night almost always descends below the level of what one has gained by sadhana in the waking consciousness, unless there are special experiences 
of an uplifting character in the time of sleep or unless the Yogic consciousness acquired is so strong in the physical itself as to counteract the pull of the subconscient inertia. In ordinary sleep the consciousness in the body is that of the subconscient physical, which is a diminished consciousness, not awake and alive like the rest of the being. The rest of the being stands back and part of its consciousness goes out into other planes and regions and has experiences which are recorded in dreams such as that you have related. You say you go to very bad places and have experiences like the one you narrate; but that is not a sign, necessarily, of anything wrong in you. It merely means that you go into the vital world, as everybody does, and the vital world is full of such places and such experiences. What you have to do is not so much to avoid at all going there, for it cannot be avoided altogether, but to go with full protection until you get mastery in these regions of supra-physical Nature. That is one reason why you should remember the Mother and open to the Force before sleeping; for the more you get that habit and do it successfully, the more the protection will be with you.