Let's be absolutely clear about this: the level of stress in teaching is a national disgrace in the UK. The disgrace comprises not only financial cost - the levels of absence, the abandoned careers and wasted training; but also wrecked lives and relationships, and debilitating mental and physical illness.
Some professional careers - soldier, nurse, social worker - are completely understandable in terms of stress: they deal with trauma as an inevitable consequence of what the job involves; it goes with the territory. Teaching, on the other hand, is not inevitably and logically a stressful occupation; not for those who love children. Somehow, however, when the lists come out, teachers are right up there with bomb disposal, oil rig divers, and paramedics. Of course some of the lists are not terribly reliable, but the consistency of this phenomenon suggests that there is a major problem here. If you really must have facts and figures to convince you of this, read here.
There are similar lists, of course, in different countries, and these international indicators make the UK situation look even more shameful. These suggest that it is not really 'teaching' which is so phenomenally stressful, it is teaching in the UK. The logical corollary is that it is only stressful because UK politicians, school leaders, and parents make it that stressful, or allow it to be that stressful.
If you seek to survive and thrive as a teacher, therefore, it is really important that you understand and manage this key issue. So let's start with the basics. There is one really important distinction which is vital in order to understand Stress. It's really obvious, it's really simple, but - for some reason I don't understand - it is missing from virtually all the teacher training material on the subject. This key point is explained here.
So, we have not one stress problem but two. Firstly, our environments are frequently too stressful (WISE) - this is basically a management failure. Secondly we - the chalkface teachers - suffer from stress too much (SFS). These two problems overlap of course, but they are different problems. If this isn't clear to you, or you disagree, read the comparison of WISE vs SFS symptoms here. You may also note that the typical causes of stress in teaching are partly related to WISE, but are not entirely so - read here.
SFS - Suffering from Stress
The fact is that there really no excuse for the levels of stress that we tolerate - there are a host of well-tested counter-measures; we just don't use them, because we don't have time, because we don't know about them, or because - well, whatever the reason, we don't.
The set of countermeasures - The Stress Armoury - is listed and explained here. However, it will help you if you have some knowledge of basic stress concepts. Firstly, make sure you understand the history of stress as a concept - it's meaning has changed, and teachers frequently have old-fashioned ideas about what stress means.... Read more here.
WISE - Working in a Stressful Environment
The onus is on the management of a school (its governors and leadership) to moderate the level of stress placed on teachers. How to do this is beyond the scope of this website - we are not a management consultancy - but basic principles are given here. Brief practical advice is given here.