Poor nutrition doesn't help your body fight stress. In fact, it adds stress to your body. Unless you use up those chemicals by actually fighting or running away, they can cause harmful physical and mental effects. Exercise helps flush out those biochemicals. Know how many hours of sleep you need and make sure you get them.
Sleep needs are different for each person, but vital to a successful stress reduction plan.
Few people thrive on fewer than 7 hours of sleep. Learn to relax. Relaxing your mind and body is a skill. Check your library for books and tapes that show you how to relax. Practice the techniques that work best for you so you can use them when you feel your stress level rising.