I would stand and look out over the roofs of Paris and think, "Do not worry. You have always written before and you will write now. All you have to do is write one true sentence. Write the truest sentence that you know.
I used to play cello. My mother kept me out of school a whole year to study music and counterpoint. She thought I had ability, but I was absolutely without talent.
Cowardice, as distinguished from panic, is almost always simply a lack of ability to suspend the functioning of the imagination. Learning to suspend your imagination and live completely in the very second of the present with no before and no after is the greatest gift a soldier can acquire.