There are many different levels of stress and from just reading your message- I’m not sure how stressed you get. Severe cases of stress require doctors and sometimes medication but I hope for your sake that you aren’t’ there yet. If you do have major troubles with dealing with stress then I would suggest that you have a chat with your GP he/she may be able to offer you more professional advice and may even give you specific exercises for dealing with these issues.
There is of course the famous ‘stress ball’ exercise which can actually be extremely effective in relieving anxiety. Stress balls are enough related to anger i.e. it’s much better to project your anger physical on a small foam ball rather than punch a hole in the wall. Stress operates in a very similar way to anger in the sense that once translated into physical frustration it may spiral into uncontrollable behaviour.
Deep breathing exercises are a fantastic way to calm you down and prevent your emotions from heightening. When you feel yourself getting stressed just take a deep breath and relax your shoulders.
If these simple exercises don’t work and your stress persists I would advise that you do talk with your GP even if it’s a one-off visit you may find it beneficial in the long run. I am including below a few links to helpful pages which highlight ways in which stress can be managed:
The following link won’t help you during tests but can be a really good thing to do when you come home for school/work and it only takes 90 seconds!