The first and most important thing you do is set boundaries with them. If you don't like their behavior, you must inform them that it is unacceptable to you and that they should not repeat it in the future. After that, have less interacts with with them.

If you are continuously affected by a toxic person and they mistreat you, do not tolerate them and respond immediately. Also, instead of becoming demotivated, seek solutions to problems and how to tackle them.

If the level of toxicity increases over time and has an impact on your mental health and well-being, it is time to leave because they do not deserve you.