I hope you find some resolution to this soon. A simple mistake can open up a lot of doors for anxiety, like you said.

Maybe think long and hard about the good things you've done for the company. It will boost your mood a bit to think about how your unique actions in other situations may have contributed good things for the company. Also, then if you ever get confronted for a mistake, then you would have some evidence to defend your position also.

It's also pretty apparent from your couple of posts that you do genuinely seem to care about doing a good job. And honestly, if that's resonating from just two posts, I have to imagine that other people you work with can also tell, and that speaks volumes. I've seen countless people get fired because they stopped caring about their work and slacked off. I've also seen a lot of others KEEP their jobs despite some big costly mistakes, because they cared enough about the job to correct themselves and be better next time. You're worthy of a second chance.