Celenia D10 System CD10: Traits and Skills: Low Self-esteem

No matter how hard you try, you are constantly besieged by a nagging feeling of not being enough. The trait is used every time you must muster your willpower, courage or stubbornness to overcome adversity. The Keeper may require a check against this trait for you to not simply give up. Others may help motivate you to either make the check easier, or to bring you back on your feet, emotionally speaking.

Overall you should also incorporate this feeling of inadequacy in your roleplay.