Anger is a normal healthy emotion that we all feel as a signal when something is wrong in our world. Anger is not inherently bad. However, how we express our anger is typically where the problems lie. You are taking the emotion out on yourself and your surroundings in an excessive way. You need to first learn to identify what you are really feeling and what is causing it. The next step is to learn alternative coping skills, such as taking a deep breath, giving yourself a time out from the situation, writing down the problem and all the possible solutions before deciding how to proceed and so on. Hurting yourself is only making the problem worse.
The other issue is low self-esteem and lack of self-confidence. On one hand these may come with age and maturity (you are at a difficult age when things are changing fast), but there are still things you can do to make improvements. To name a few: make a list of all your positive qualities and add to it as you think of new ones, spend time with positive people and doing things that you enjoy and feel comfortable doing, and don’t EVER expect perfection because you will always feel disappointed.
You would also benefit from seeing a therapist or joining an anger management group for teens. At a minimum, do a Google search on books and workbooks on anger and self-esteem. There are many available that are written for teenagers. Hope these suggestions help.
All the best,
Dr. Holly Counts