When you are tired you sleep. Because you have learned that if you go to sleep you will get the rest that your body needs. When you are under stress you react in the various ways you have learned to react over the years. There are some very simple and extremely effective ways to reduce the amount of stress you are experiencing and these methods will work immediately. You can accomplish these states very quickly and do not require any special training to do so.
Stress is a mind state.
You have the ability to change your state simply by thinking of something else and concentrating on it. I have a bay window in my home office and when I get stressed I like to look out into the world and day dream about fishing, my favorite pass time. You can do exactly the same. Contact your secretary or assistant or get a neighbor to come over and let them know you do not want to be disturbed for about ten minutes. Then sit in your chair, stretch out, take a deep breath and let your mind slide into your favorite place.