Well, it happened, and sooner than I had expected. Driving on the left feels normal.
How do I know? The other night Sharon and I were watching a movie (Burn After Reading, which is absolutely hilarious), and there was a shot of a car driving down the road. Both of us gave our heads a shake and said "Hey!" Then realized that, no, there wasn't anything wrong with the film. The car was indeed supposed to be driving on the right side of the road since the movie is set in the U.S..
Fortunately, driving on the left has felt normal for a while. Even if I do go around to the wrong side of the car at least once a week.