I simply say to myself, "I'm not what they are looking for." I simply let it go and move on. You have to work on being yourself because a human being is a work in progress. Nothing is perfect in human beings except in the design of the human body. It is what is inside that counts. However, individual qualities cannot be seen by everyone until the time for the individual to rise from obscurity.
Just concentrate on being yourself. Focus on your strengths. Your health is very important and it should not be taken for granted.