Also, ask yourself, is there anything you did in class to make her not have a good opinion of you (such as acting up in class or not turning in work or handing in assignments late)? If so, then work on improving those things.

I’m sorry that your ex-BF is dating your ex-friend. It’s not a good feeling, but maybe you should keep in mind that he is your EX-BF, and it’s better than him dating your friend while he’s still in a relationship with you.

Have I turned in all my homework?

Do I participate in class?

Do I try my best?

Do I try to get along with my teacher and classmates?

Do I have a positive attitude?

Do I study for tests and for school?

Do I respect my teacher and classmates?

If your answer is no to any of these questions, then it is your job to “undo” these problems by becoming a better student. Talk to your teacher. She/He will not only explain what the problem is, but she/he can tell you what you need to do in order to improve. By the way, there is getting around a scolding from your mom. But of course you knew this when you started behaving badly at school. So, accept the consequences of your actions and learn from them.

You also mention your boyfriend who went back to his former girlfriend. Again, take control of your life and ask yourself this question: Is he worth it? From his actions you can see what he is really like, what his priorities are. You can not make someone love you. If he really loved you, he wouln´t treat you this way. But, if you really loved yourself, you wouldn´t let anyone treat you this way.