To better develop good self confidence determines what you are saying to yourself about yourself. I am great i am positive and i am happy is just some examples of words of affirmations that you use daily. Use as simple as the way you dress as a boost to your self confidence not a lot of emphasis on it though because you may need to budget on that area. Be who you are you are a young man determine to make right in your life recongnizing where you are and where you ought to be. Yes journaling on this forum help me alot. Reading help enlighten my mind to examine my thoughts and other people mindset and what they reveal about themselves on this forum and books i have read. So you can occupy your time by doing something you love before you started gambling. A new hobby reading writing drawing etc playing sport going to the gym will help you to boost your self confidence. You are going to accomplish great thing man.
Keep your mind free and live your life bro. Life is meant to be enjoy.