Your brain is like a circuit switch. Once you believe you are something, you embody that feeling. If you were in a coma and you woke up with no memory and you were told that you used to be a navy seal and they want you back now when you're healthy, do you think that you'd hold yourself differently? Do you think you'd have a different self concept of who you are than if you were told you were a piano instructor? Being successful in life is all about having the proper belief system in who you are. Truly believing that you are something unique and that you are something special in that field. Since a brain is like a circuit, when you introduce it with the proper wiring, you're going to go straight towards your goals. If you're unsure about who you are, than your dreams and goals will never become a reality. Everyone has mental doubts and internal conflicts in life. Even the most successful people that you look up to but they don't live there. Its how you handle those negative thoughts in that exact moment and overwhelm them with positive action and that comes with the upmost confidence in yourself that you can handle this situation. Trust in yourself that you are better than the moment.