This is the problem, including when you get back home!! I did this after driving three weeks in NZ, driving down a quiet street and wonder why the car approaching is in my lane.

Last week there was a car travelling the wrong way around a nearby roundabout, likely back from holiday.

We have folks living up the road who moved from the UK. One day while on her way home, the wife saw John pull out of his driveway and onto the road into the left lane. She hung back and watched as he drove about a half mile before he saw a car coming the other way and quickly remembered which side of the pond he was currently on.
Hope you're having a great time, unclebilly!

Best
Les

Your most dangerous time will be on the second or third day, when you feel comfortable, that’s when you’ll see headlights approaching head-on. From personal experience. Stay paranoid for the first week if you can.