Messed up at my job, how to move away from feeling like being a fraud?

As you know executing tasks sometimes is very hard but it bit me in the ass today. I am fixing it, but I hate that it had to first get to this point for my brain to get creative and the push I needed to get things done. I have been struggling with feeling like a fraud and a failure (I am going to therapy) but today was really tough. Sorry this was more of a vent, but maybe it will get better with time and effort.