The very act of writing has been scientifically shown to be a beneficial creative process. By putting pen to paper, you are using the left side of your brain, which is critical and rational. This gives the right side of your brain a chance to access your feelings and intuition without any mental blocks.
Once you begin to completely accept yourself -- in all your guts and glory -- you'll be able to come back to yourself and reclaim your truth. To do this, you need to silence the chatter. The only way you're going to learn what your own voice sounds like is to detach from every other voice out there.