Meditate
When your brain starts buzzing, meditation can be just the medicine you need to silence those pestering thoughts. When we are stressed, our minds can become overwhelmed as we run through our to-do list, try to tackle the task at hand, and predict forthcomings. When you feel like you can't think straight, take a time out rather than freak out. If the idea of meditating (especially at work) sounds laughable, let it be said that meditation doesn't have to consist of sitting Indian style and humming. Just closing your eyes, concentrating on your breathing and being focused on your current state (not what's going on in your head) for a few minutes can do the trick. For newbies an app like Headspace can help you get the hang of getting Zen.