Do this simple exercise:
Write your name down on a piece of paper like this
Next underline it
Underline it some more and put exclamation points!!!!!!!!
You are important. You have accomplished so much and have touched many peoples' lives whether you know it or not. You have so much to offer to this world. Don't sell yourself short. You can conquer anything and everything this world will present to you. You will go on to do great things; the only thing needed is that you apply yourself. NOW GO OUT AND GET IT!