Try to sit comfortably in a place where no one will disturb you. Ideally on the floor, legs crossed in a half lotos, but you can just sit on a chair with a firm, flat back. Close your eyes. Tune in to your breathing. Try to feel it. Try to relax your body as much as possible. The point is to be as relaxed as possible and as collected as possible at the same time: ideally, the body should be completely relaxed and attention fully focused on breathing.
Then take a deep breath that is most comfortable for you, synchronizing it with a count from 1 to 9 during inhalation and from 9 to 1 during exhalation. This should not be breathing exercises for survival, that is, the depth of inhalation should be maximum, but at the same time comfortable - do not strain! Breathe in until you feel that the counting and breathing are as synchronized as possible.
When you get used to breathing this way, breathe in shorter and count to six.
Then you can count to three (short inhalation) and to one (the shortest inhalation-exhalation, like a swing : one-two, one-two).
When you learn to synchronize counting and breathing at different depths of inhalation, do the same, but without counting, trying to concentrate as much as possible on the sensations of breathing. Try to monitor how air enters and leaves your lungs. The duration of inhalation-exhalation can be different, but without counting: you needed the count as a support, now you can do without it.
At the third stage, concentrate not on how the air passes through the body, but on the place of entry and exit of air, that is, on the nostrils. Catch the sensation of inhalation: which nostril is breathing (let, for example, you have a chronic runny nose and only one breathes normally - sweat which one and concentrate on it) and observe how the air enters and leaves the body.
Ideally, you first need to master counting, then observe the inhalation, then observe the nostrils. And then combine different methods of observation. The stages should go sequentially in forward and then reverse order, for example: first, count to 9, then to 6, then to 3, then to 6, then to 9 ...
Do this exercise every day, at least minutes for 10. Ideally, bring to half an hour. Ideally, up to half an hour twice a day: once in the morning and once in the evening.
This is called anapanasati meditation (mindfulness of breathing). More precisely, one of the ways to meditate in this way (there are a lot of them). It soothes the nerves very well, especially with regular use.
From my own experience, I will say: any methodical measured activity that does not require an intellectual load helps to relieve that very tension. Sometimes, doing some kind of work with your hands, willy-nilly, solutions to some problems come, which can also cause / increase tension. Among these types of activity:
1) Cleaning. Start small, put everything in its place on your desk, one shelf, at least on the shelf in the bathroom.
2) Cooking. Probably a purely feminine approach, but who knows? Suddenly you will be inspired by this kind of creativity and discover something new for yourself.
3) Sports! Muscle work, physical stress followed by physical fatigue help to strengthen not only the "rolls", but also the nervous system. And a beautiful body is a great bonus!
P.S. Nervous stress leads to the depletion of certain trace elements in the body. Just think, when was the last time you took a vitamin course? Consult a specialist.
The tension appears when you drive yourself. Take it easy on everything. There is even such an expression: "What is it to me? Power in indifference!" Do you need to do something? You just do it! What do you want? You just do it! Because I decided so and because you need it.
It's a great idea to have a good time, the main thing is to have an opportunity to sleep off and relax in a calm atmosphere without booze. Because alcohol is a depressant and lack of sleep is also a depressant. Stress is created by uncomfortable conditions. Allow yourself peace and comfort, at least for a day.
Since I am not an adherent of healthy lifestyle, I would recommend drinking beer stupidly. If you need to relieve tension very quickly, then strong varieties that are called "malt-liqueurs" in the West will do: "Baltika №9", "Okhota Strong", "Bear-beer", "Amsterdam navigator". They are also excellent sleeping pills when you can't sleep. The main thing is not to get carried away ...