I came across the question tonight on an online art forum. It's a question that generally comes up for people who make art, at some point, usually earlier on, maybe a few years into really working at it, and it's a worry that can be devastating.
Many understanding artists (because, yes, we've all had to deal with this) responded with encouragement and great advice.
Here's a slightly edited excerpt of what I wrote....
So, in order to keep making art, you have to learn how to get out of critical-mode.
If you can get into that mindset — what you do is learn as much as you can about making good art, and then you just work at it. Consider it research & development.
Then you have 10,000 (or however many) hours to learn how to make art without your critical voice popping up. Make the most of it! Working from your creative side, rather than your critical side, will become a wonderful habit, and you will be able to make art. And the more you do, the better you get.
It's like the old joke about how you get to Carnegie Hall... practice, practice, practice....