The Rules of Golf

I realized the other day, after consulting the rules of golf, that I was in err on October 18th when my playing partners ball hit mine while it was at rest further down the fairway and I proceeded to play my ball as it lay. Turns out I should have replaced my ball where it lay before it was struck by his ball in motion but I did not. I should have assessed myself a two-stroke penalty for the hole and signed for a 7, not a 5. My apologies to the karmic gods of golf--I acted not out of selfishness but of ignorance and I promise it won't happen again. Seriously though, given that I and the rest of my playing companions were some 200-yards down the fairway when the collision of golf balls happened, I'm not sure how I was supposed to realistically assume with any accuracy where my ball had originally come to rest. It seemed more "accurate" and perhaps appropriate to just continue the hole playing my ball where it lay after it had been moved by my opponents ball. Oh well, live and learn.