One of the central problems for you if you are anxious is your fear of making a mistake and your fear of being rejected. I don't know about you, but I sure have a long history of rejection---only because, I think, I have constantly been trying to be productive. When I was single I was rejected by girlfriends-but accepted by some. I have had book proposals and articles rejected. I view rejection as part of the cost of playing the game. You won't be able to win unless you can tolerate losing some.
If you wonder if other people have made mistakes, here is a list of authors and books that have been rejected by publishers when first submitted. The authors include James Joyce, Vladimir Nabokov, Sylvia Plath, Jack Kerouac, Jorge Luis Borges, Isaac Bashevis Singer (who won the Nobel Prize), Marcel Proust, Stephen King, Oscar Wilde, and George Orwell. Famous books that have been rejected include The Diary of Anne Frank, War and Peace, The Good Earth, Gone with the Wind, Dr. Seuss, To Kill a Mockingbird, The Rubaiyat of Omar Khayam, Watership Down, Lolita, Angela's Ashes, Harry Potter and The Hobbitt. The editor who rejected the classic book, Animal Farm, by George Orwell had this piece of wisdom: ‘It is impossible to sell animal stories in the USA'. Another brilliant observation-and a classic mistake- was the following: "Everything that can be invented has been invented", claimed the forgettable Charles Duell, Commissioner of the US Patent Office in 1899. Or consider this: "I think there is a world market for maybe five computers."(Thomas Watson, chairman of IBM, 1943). Or, one of my favorites: "We don't like their sound, and guitar music is on the way out" by Decca Recording Company when they rejected the Beatles in 1962.