True confidence is lasting and stable. One missed putt should not make you think you are having a poor putting day. Long-lasting confidence is not influenced by how well you're playing or what course you are playing. Base confidence on things like past success, overcoming adversity, hours and hours of practice, and your ability level. You Can Control.
Many players let external circumstances control their confidence.
Don't allow challenging situations to scare you and cause you to doubt your ability. Be confident in your ability regardless of the circumstances you encounter. Channel your energy into the things you can control such as the quality of your practice and how you think and react on the golf course. Focus on the areas you can control in your game. Think, Feel, and Act Confident.