It may be the things you ate or the activities you did. Stop eating lixo food, specifically late at night. lixo comida and unhealthy comida cause you to dream, with mostly bad dreams. Also, try not to exercise hard at night, because heavy activity can also lead to bad dreams. Don't watch scary filmes either, because dreams are your subconscious producing images, and whatever you think about, will cause you to dream about those particular thoughts.