When our body is stressed, it is telling us that it wants to fight or run away from danger, just like thousands of years ago when an encounter with a wild animal was a daily occurrence. Nowadays, in the domestic or workplace situation, this is completely unnecessary and, indeed, inappropriate. Imagine that your boss is ticking you off about something. Internally, your body is telling you either to get away from there or fight back against your boss. Either of these responses is inappropriate, even if they take the form of having a day off work instead of literally running away, or answering your boss back rather than clubbing him or her over the head.
These kinds of internal responses, which are intended to protect you from harm, are pointless in the modern context of work and home life. Instead, you need to develop a different, natural way of responding. You need to develop a relaxation response! Relaxation is a completely natural response, you just need to learn how to do it.
Stress is a medical condition and it can have a serious effect on your health. If you think you are suffering from stress it is crucial that you consult a medical professional.