Visions of Hell Realm in Contemplation- What does it mean

Yesterday while reading a book suddenly my mind generated the following visions: I saw a girl in a white dress being tortured in this very unpleasant place which smelled bad and was horrible , I saw her being raped by this creature who looked horrific , again and again these visions came to me in the night. What could these visions mean ? Are they trying to warn me of some bad karma ripening. As it is said by many Tibetan teachers that they get warnings of future happenings in dreams. Although this was not a dream.