You’re lying in bed, your mind is racing and you can’t fall asleep. And it’s already 3 am, meaning you’ve got to get up in just two hours. And you’ve got important things to do the next day, which means you need to be sharp, which you won’t be, which is something else to worry about. Sound familiar? First of all, brooding is normal and not necessarily a problem. “Everyone broods now and then, ruminating without coming to any conclusions,” says Dieter Riemann, head of the Department of Clinical Psychiatry and Psychotherapy at the University of Freiburg Medical Centre in Germany. But it’s import…