The key to performing well in an exam is preparation, preparation, preparation. However, exams can become physically and mentally draining on your child and sometimes, no matter how much they may be prepared, stress will can get the better of them.
Here's how you can help:
Understand stress
Stress can actually be good for your child, often motivating them to get work done and push themselves that little bit harder. However, it is important it doesn’t take over so that it becomes unmanageable. Bad stress is counterproductive and your little one can start to lose their concentration if they are too stressed. It can also lead to feelings of anxiety and being highly emotional thus causing tears and tantrums, even in older children.
Praise them
Bad stress is usually caused by your child’s lack of faith in their abilities. This can lead them to become short tempered and irritable. Praising them and showing them that you have faith in their abilities might be enough for them to take stock of the work they have done.
Don’t blame them
If your child’s stress is down to them not having prepared enough, telling them it is their own fault won’t help the situation. Try to help them see the positives and to remember what they have gone over. 
Give them some help
When your child is stressed they can start to lose focus and lose track of what they have to do. Panicking, they may try to squash as much study in as possible without any real direction. Helping them to build a workable study timetable will give them a sense of focus and another person’s perspective may go a long way.
Give them other options
It is important your son or daughter understands that there are other options out there. The worry that not passing a particular exam means their hopes and dreams are gone can be enough to send them into a complete stress spiral.
Encourage them to exercise
Exercise is a great stress reliever. It takes your son or daughter’s mind out of the books for awhile and also helps to boost memory and improve sleep.
Encourage them to reduce caffeine intake
Caffeinated drinks such as tea, coffee and some fizzy drinks can make your child feel anxious, hyper and unable to focus. This will just add to their feelings of stress, making them feel a lot worse.