We all have our insecurities. You might not have accepted your body for the way that it is or you might have been bullied in school for the way that you are. Insecurities stem from long before your current self and can be triggered by simple comments online. It is something that your parents usually think you will grow out of or simply fail to give much attention to. Every night before you go to bed, you might find yourself thinking about things that attack your insecurity, and even if it is something that seems very insignificant to other people, it is simply something that bothers you much more than what would seem rational.
What can help you find peace with your insecurities is to rationalize them. Perhaps you would find peace if someone explained to you or if you could figure out on your own why some things bother you much more than they would others. You could use a therapist for this. He or she would hear stories from your life and help you connect the dots to rationalize the insecurities that you have. Once you have done this, you might start to realize that the problem is not as big as you have let yourself believe. You can let go of this now-rational insecurity.
If you are unable to find this rationalization, then you might need to find a coping mechanism. Some people find their coping mechanisms in drugs or alcohol. These are not healthy solutions. You need to find more healthy ways to burn off your steam. You could find peace through a sport like swimming or squash. You could, otherwise, hit the gym. Letting your insecurities sit and avoid facing the problems will only delay your acceptance of yourself and deteriorate your mental health. Instead, it is best if you start facing them for a better tomorrow.