This is actually one of my favorite songs as well. It's a masterpiece through and through.
I think its normal for musicians to be overly critical of ourselves. I don't think I have ever recorded a song and thought "It's perfect", no I always feel like I can do a better job, and I believe that is a key ingredient for growth and improvement in ones abilities.

Don't even worry about the mistake! It didn't take away from the integrity or quality of your performance in any way.

By the way.. If you want a good laugh, watch my recent submission, and the very last chord of the song, I play a minor, when it's supposed to be a major. I'm not sure if you can tell by the expression on my face or not when it's over, but I was just thinking "well isn't that just my luck" lol

much love