My self doubt is getting ridiculous

Those couple of days I finished some work for a client and I gave it to him and all was perfect. Until I got a message from him saying there's a mistake..

In my head I was like that's it I'll never do anything right, I'll continue messing up everything I do, every opportunity I get. I was willing to give him a refund. I was doing something so I couldn't see the message right away and I was mentally preparing for how I'm going to fix this.

Then I opened the messages and turns out it was his fault, he gave me his email address but he spelled it wrong and he was the one apologizing.

I think I need to relax especially because I'm making a career shift and learning new stuff so I can expand my horizons.