Stop being so self-deprecating, man. You're a good writer. And deep down you know it and you gotta listen to that part of yourself just as much as your internal critic. I struggle with my shit a lot. The thing you gotta do is keep trying and not get yourself down because in the writing industry, there are plenty of people who will do that for you. Be your best cheerleader as well as your harshest critic. If one overpowers the other though, things don't go well. :/