Self Doubt

Self doubt. We all have it, right? I want to have faith in my book, but there are so many writers out there that I'm competing against. I'm afraid of that narrow line between arrogance and confidence. I've never been particularly arrogant about myself, but when it comes to reading other people's ideas and writing...I feel myself being judgmental, and I hate that. And I know other people are judging my work and I want to know what they think...but I fear it, too. What if I just THINK I'm good? It's all a matter of opinion.