What's your biggest hurdle right now?

Right now my biggest hurdle is myself.

I'm not a very good coder. I don't know much about marketing and I don't know if my app will sell once I launch. This worries me. But I'm pushing it everyday. I'm writing code and I'm trying to learn whatever I can about sales and marketing. I'm talking to people and trying to get better so that I can increase my odds.

Am I the only one with so much of self doubt and fear of failure? Do you fellow Indie Hackers also feel so sometime? It would be helpful if you share how you deal with it.