Many have been struggling through this, even myself once in a while. Found an interesting article here, I hope this helps. http://www.artofmanliness.com/2008/01/10/increase-your-manly-confidence-overnight/

The question actually is rather strange, in regard to the proper answer. If you wish to practice Self Reliance, I cannot help you. That would be the case if you insist upon having confidence "in yourself". I have Confidence, but it is not in "myself" but in God. As big as God is, that is how much confidence I have. If you demand of life that you have confidence in you, there is literally, absolutely no reasonable counsel I can offer. I would not even have confidence in my own Self. In fact, the current theories of modern Science show that no such thing as a SELF exists. So, one might as well ask to be shown how to have confidence in their muscles, or bones, or their Toes. I have no answer to any such question. The deeper question which emerges, is this. Do you believe that a Transcendent SELF exists? What is the nature of such a SELF? How is such a SELF to be manipulated, directed and so forth? Does a SELF exist in a Cause & Effect Relation to natural phenomena? .

Nothing is perfect in this life, so I simply think I am not perfect and it doesn't matter, then I can get more confidence.