The key is to stay positively focused on what you can control - easier if you take control of your own frame of mind first.
GET MOVING before worry takes hold. Try a quick burst of vigorous exercise - eg, running up and down stairs. This diverts your attention and releases tension.
EAT STRATEGICALLY. Start the day with serotonin-boosting foods such as a banana or grain cereal. Make lunch a high-protein energiser, dinner a plateful of relaxing carbohydrates.