I don't have a reference handy, but I've read a few books on success, and there are studies that kids (and adults) who have the mindset of "This is great, I'm awesome, everything will be a piece of cake" -- the ones whose parents tell them they're amazing to build up their self esteem-- are LESS likely to succeed than those that find a task challenging and frustrating. So really high self-esteem can actually hurt you.
The way low self-esteem hurts you, though, is by stopping you from working. As Bertie said, it saps your energy.
So don't try to think "I'm awesome." Try to think "I am dedicated to this. This is important to me and I want to work hard to succeed." Believe in yourself, but don't believe you're already a great producer. Believe you're a dedicated learner who is willing to do something hard until he succeeds.
And it *is* hard. I've been working on electronic music for about 25 years - yes, I'm old. It's never been my full-time job or even full-time hobby, but I've spent thousands of hours on it. And it is still hard. I won't say it's the hardest thing I've ever done, but it's certainly not a piece of cake.
Also, the number one thing that helps with my self-esteem as a producer -- and it took me about 20 years to learn this -- is to FINISH TRACKS. Every time I finish a track I know I've gotten better. Every one might not be the best I've ever done, but every one taught me something. And if I compare my latest to one I made years ago--I know I've gotten way better.
Good luck.