A good exercise program is well-known to improve how good and confident you feel about yourself. Eating healthy, making personal care a priority all have a good effect. How good and confident you feel about yourself is not immutable -- even clinically depressed people benefit from exercise (note I didn't say cured, but I said benefit -- and that is scientifically proven). Having a schedule that includes and prioritizes the steps you can take to improve your sense of well-being is a very good strategy. These things don't work in one day, obviously, but over time the effects are huge.