Not hearing back might have nothing to do with yourself, your experience, skills, achievements and so on. 

The longer the job-search takes, the more desperation might build up. Especially, when you apply and you do not receive any feedback. Your self esteem is deteriorating quickly, you doubt yourself. I am useless, I am wrong, I am not worthy and so on. A horrible place to be - but it doesn't have to be like that.