A certain normal level of stress can feel manageable or even productive. But increased or unmanageable levels of stress can mean you feel constantly overwhelmed and that there is little or no relief from this sense of pressure. High stress can begin to affect your ability to perform your responsibilities or tasks and impact on your relationships.

If you feel highly stressed you might find that you can't think clearly or decide what to do first, or decide what to do at all, which will increase your stress, and can also result in negative consequences and increase all your physical stress responses and this, again,increases your stress. Anxiety, perfectionism, and unrealistic expectations of yourself or from others can greatly increase stress

1. Breathe.
One of the things that happens when you are stressed is that your breathing becomes shallow as if you are almost holding your breath. This causes alarm reactions in your body at a purely physical level. Notice your breathing. You can even set an alarm on your phone at least once an hour to bring it to your attention. Breathe slowly and calmly. Bring your body systems out of panic. Find a mindfulness CD or exercise that works for you so you can build this muscle daily and learn to decrease your physical stress response.

2. Get into action and stay in action.
When you are too stressed to make decisions on what to do first, decide to get into action anyway. Make a decision of what to do in the next half hour and stick to it and do it, get something done, anything. Set a timer. At the end of that half hour take a five minute break, make a drink, walk down the corridor, sit outside for 5 minutes. This can be as simple as doing the dishes, taking the dog for a walk,doing one small thing on your must do list for the day, making a list of what you need to do. Decide what to do for the next half hour. And so on. Taking action lowers your stress response and helps you engage your prefrontal lobe so you are thinking rather than reacting. Balance this with regular breaks.

3. Plan.
Despite all the research into effectiveness one simple tool shows up time and again. Write down everything you need to get done and want to get done today so it’s out of your head and on the page. Choose a maximum of the five most important: the first five steps of one large task, or five separate tasks. Number them in order of importance. Focus on the first one until it is done, then and only then do the second and so on. Do this every day. Taking the time to do this will help clear your head and lower your stress response. Notice too if you ever get to do the things you want to do, and if not, why not?

Full Catastrophe Living: Using the Wisdom of Your Body and Mind to Face Stress, Pain, and Illness. By John Kabat-Zinn, M.D. The heart of the book is based on Kabat-Zinn’s renowned mindfulness-based stress reduction program at the University at Massachusetts Medical Center.
Note: Any books by this person looking at mindfulness, offering mindfulness meditations and ways of understanding mindfulness are useful.
Spark. By John Ratey. This book presents new research on the the vital link between brain health and physical movement. Will increase your understanding of how and why regular exercise improves your concentration, mood and resilience to stress.
The Reality Slap. By Russ Harris. Learn how to cope effectively when life hurts or causes anxiety. You can also download an MP3[link] of the exercises in the book, very useful for developing self-compassion and learning to address anxiety and lower stress levels.