It's very normal for you to have worries sometimes and often they will go away on their own or you will have a way of sorting them out. But when the worries make you upset, it is best to tell a friend or a grown up at home or school.
You might want to speak to someone at school but don't know who are how.
Perhaps you could talk to your teacher or a TA. Maybe you would feel happier talking to the teacher you had last year or Mr Martin. We will always find time to listen to you and try and help you to make those worries go away.