Mood swings. We all have them. One day you're on top of the world, and the next, you can't get out of bed. It seems like your mood is constantly changing for no reason at all. It's perfectly normal to have days like that now and then. What if they disrupt your life and prevent you from living the way you want? Here's a closer look at mood swings and how to tell if yours are a sign of something in need of attention.