Who Am I?

I've been told that I am loud and obnoxious, but I'm quiet and speak when spoken to. I've been told that I am such a merciful person, but I recently took a test that showed mercy to be my least used gift. I've been told that I am a great speaker, but I get nervous and stutter in front of people. I like to make people laugh, but many times I'm simply not funny. I have a feeling that I will do something big, but I feel so small, useless and unnecessary. I love, but at times feel unloved. I think i'm fit, but injuries keep me from being at my peak physical physique. I believe that I am a good writer, but my grammar is horrendous. I have dreams, but not all have come to be. I've been told that I am a good person, but I feel like the goodness is a disease that has taken over me and I no longer can help myself. I want to believe in something, but what I believe in has brought me to where I am. I love music but sometimes I cannot stand the sound of it. I say one thing, but I do another. I know who I am, but I am unsure of myself. Who am I?