Hello 
 Thanks for your query.Based on the facts that you have posted it appears that you have  
 been indulged in 
masturbation frequently.Masturbation is very common at the age of adolescence.
First of all there is myth in a mind of common man that excessive masturbation can lead to some problems in sexual activities in future. But I would like to state that it has been discussed in scientific forums all over the world and proved scienificaly that masturbation does not have any negative effect on any organ or system in the body.
. Following measures will help to boost up your level of confidence and allay 
anxiety and there by improve your sexual performance, 
1) Practice moderate exercise for 45 minutes followed by 
meditation for 1/2 hour. 
2) Take high protein diet rich in 
vitamins A,C,E,D.fruits and vegetables . 
3) Avoid alcohol and 
smoking . 
4)Take some anti oxidants like Almonds 5-6 everyday. 
Avoid getting addicted to it.
Dr.Patil