I can understand not being bothered by a spike in your sex drive. (We were all 18 once.) And others are addressing your hunger problem. However, I have a question about the mood swings.... do you think they are related to your exercise or diet, or perhaps something else? 18 is a difficult time - you are figuring out your future, among many other things. Are you stressed? Stress can cause mood swings down and up, hinder or increase your sex drive, and, yes, cause you to overeat by making you think you are hungry. Perhaps you could speak to someone who could give you some counsel - at school, a friend of the family, a priest or pastor, or some other adult figure in your life?