Hi thanks for writing to me
This can be quite a common thing to happen to anyone who is feeling stressed out. The body can react in different ways when we are in stressful situations.
Some people get bad headaches or backache. Some can experience tummy pain and sickness, like you do. It's the body telling you that it's not comfortable with a situation.
It could be worth talking to your mum and dad and say this is what happens when they shout or talk to you. They probably don't realise that this is the effect their concern and worry has on you. More than likely, once you have have done this you may be able to relax with them.
You know parents are really very understanding people even though sometimes they don't always show it. They were young too and sometimes they can forget this.
Have a chat with your mum and dad, and it may be a good idea to ask one of them to make a doctors appointment for you, just to get yourself checked over to make sure there is nothing else wrong.
Hope this helps
Take care
Sam