No lie — I did the exact same thing when I used to run a charity auction for a local nonprofit organization I used to volunteer with. I approved a set of flyers advertising the auction but didn’t notice that it said 2015 (this was in 2016). And it worked out pretty much the same way for me as it did for you — the printer noticed the mistake himself and changed it for me, so there were no issues. But I freaked out so hard when I first realized what I’d done.
Being too hard on yourself is definitely a difficult thing to unlearn, but it’s so much healthier if you can break away from it. It does take a certain amount of time and effort, of course, but it’s totally worth it in the end.