Don't be afraid to talk about it. If the person you tell is not listening then tell someone else who can help.
Keep a diary of feelings. Writing down how you feel might get it off your chest and help you feel better.
Go for a walk or bike ride. Exercising often makes us feel better and changes our mood.
Try to do something you enjoy like see a friend, play football or make something
Listening to your favourite music might take your mind off your worries and will help you to relax.
Tell a grown up so they can help stop it. Otherwise it will happen again and you might get hurt.