Whether it is due to a real or imagined threat, stress will make your body produce adrenaline. Adrenaline gears the body into action by increasing heartrate and the production of sweat. The stress response also swtches off any systems in your body which are not essential for short term, immediate survival. This means that digestion, sex drive and the immune system, which are all to do with long term survival, get put on hold while the stress response is operating. If the stress response is operating for a long time, day in day out without letting up then the digestion and immune function and even sex drive can be suppressed long term. This is why people become physically affected by stress.
Continuously raised levels of cortisol, which is a stress hormone, can make someone physically ill- causing stomach problems, immune system failure, and the inability to think rationally. The antidote to this is of course rest and relaxation. The best way to deal with stress is to allow yourself to relax so that your body can begin to repair itself. You also need to develop the mental skills which allow you to feel calmer and more in control when you most need to.
The best way to learn how to feel calmer and in control is by using Hypnosis in my opinion. It has worked for me and countless others who came to see me. Hypnosis helps you to relax in the moment and feel calmer in a matter of minutes. When you train yourself using Hypnosis to see things much more clearly it then becomes a matter of habit and before you know it the magic has happened and stays locked in.