Your exposure to your bad psychology and behavior is enough to show that you are determined to change your mentality. I think your mentality is enough to completely change yourself.
First of all, make a practical plan for the courses you study, and it is best to fill your extracurricular time, and then implement it step by step. Before going to bed every night, check the completion of the day's plan. If you finish the plan for one day, give yourself a reward-whether it is spiritual (such as self-praise) or material; If you don't finish the plan for the day, first ask yourself a few more reasons. Is it unrealistic to do as planned or not? If it is unrealistic, you should correct it. If you don't do as planned, you should review or punish yourself.
This practice will become a habit over time, and then you will achieve your goal.
Secondly, what I said earlier is that you control your behavior when you are rational. If you don't want to control yourself emotionally, it seems that we can't solve emotional problems with rational goals. Then we might as well ask a friend who is serious and practical in study and life to help us, let him supervise the implementation of your plan and learn good behavior habits with him.
Thirdly, if we can't do the first two items, then we will try to find something we feel comfortable doing in life, such as exercising and chatting with friends, and then make some small plans for ourselves that are not difficult and demanding, and strive to complete them with our own efforts and perseverance. If we can't finish them, we must find out the reason from ourselves. At the same time, use a notebook to record this psychological process (confusion and feelings) to promote your thinking and help you move from irrational thinking to rational thinking. Over time, it will become your spiritual wealth. When you are confused or difficult to control yourself, it will help you to improve your self-control ability.
Fourth, when you are in a bad mood and feel uncomfortable or relapse when you make a "turn over a new leaf" in a rational situation, let yourself realize the consequences first. For example, the result of this is that I can't get into college → find a job → "ruin my future in this life", and guide myself to think rationally, which can also achieve the purpose of improving self-control and self-control ability.
Fifth, if all the above methods fail, you can also strengthen physical exercise, or turn to close friends and psychologists to improve your self-control ability.