Convinced you have to make this job work else? Constantly replaying what you could have done better?
The Solution: Explore your options for stress relief
This makes no sense on the surface: if you've had a few hiccups, you should keep your head down and grind. You should solicit feedback and pray you can correct your mistakes.
Stress and fear of calamity biologically limit your thoughts, and are a circular prison which deprive you of sleep and calm, as scenarios race through your head. Keeping focused on what's not working will keep you trapped and drain the life out of you.
Release the pressure of your current situation by setting up 1 or 2 networking coffees over the next two weeks. Get out there and listen to what other people are doing in the world. Leave your heavy narrative at home, and open your ears to be inspired by new ideas.
As you begin to see that life goes on outside your current situation, your draining emotions around your current job will dramatically decline, and you'll be able to find renewed focus, and see your current challenge in a more positive light.