In the book, "The Art of Possibility" by Ben Zander, a chapter is devoted to speaking about the voice in the head.  That voice is the one that sometimes whispers to you and says you may not be good enough.  This voice can also wane your confidence by allowing you to think that you are just a little less than or it can emphasize what your shortcomings in life have been.  Some people grew up with a parent that used their power and authority to make you feel unworthy or perhaps that you would grow up just like your father, brother, etc.  Comparisons, but not in a good way.  That voice can have a lifelong effect and learning to quiet that sooner versus later is essential to your own well being.  Do not allow it to overcome your daily thoughts and beliefs.  To be clear, the voice in the head is not your conscience or when you feel your heart speaking to you.  Those are usually right on the mark.  We can be our own worst enemies, as there is no need for someone to point out something about us that needs work.  We usually have a long list ready to go.  It is key, that you begin to eliminate that negative voice that allows you to question whether or not you are worthy.  The fact is you are worthy and deserve so much more.  Keep the voice quiet and work on getting rid of it for good.  You will do yourself a lifelong favor.