Apologize to the pastor in person, tell him that you realized that this past Sunday did not go well, and that you will try to not let that happen again. I would be willing to say that the pastor has probably delivered a few bloopers during his sermons that he would take back if he could...it happens to people, we are human...if we were able to be perfect we wouldn't need a Savior, would we? Also, you might mention that the organ is not operating as it should and politely request that it be looked at by their service provider...a partially operating instrument will throw anyone off their game. (ask me how I know).
Rick in VA