Sounds like your prep has been spot on. One thing I didnt see mentioned- is it possible you're short-drawing? Not getting fully to anchor with good back tension? I found with me if I make a bad shot thats usually the cuprit. I have a mental check list when I draw on game- pick a spot, draw,squeeze( back muscles) anchor, release follow through. I run the steps through my head before I draw.
I do the same, I shoot a judo every morning before I get out of my stand. So far, every one has been within an inch of my target.
Confidence is a big facor in the mental game of archery. It doesnt take much to rattle it, but again it doesnt take much to get it back.
Single arrow cold shot practice is the best. you'll get it straightened out, just relax and let the shot happen. Dont over think it.