We all make mistakes, so we need to learn to accept them as a fact of life. Making a genuine mistake does not make you any less of a person. There is nothing to be ashamed of. There is nothing to be afraid of.
If anyone gives you an unnecessarily stressful time about making a mistake, remember they will have made just as many mistakes as you, if not more. The question 'May I congratulate you on never having made a mistake in your life?' is a useful answer here (just not to your teacher)!
Think about the following:-