I do not know whether this will help or confuse, but it is a different way to look at it:
Look into a mirror with your nose pointing North. Your left hand will point West, and your right hand will point East.
Your mirror image has a nose pointing South, a left hand pointing West (!) and a right hand pointing East (!)
You know it is his left hand pointing West because it moves when you move your left hand. Also, you may wear a ring or have distinctive features on one hand.
You know that left hand is pointing West because you can see the sun set in that direction.
So East and West stayed where they were. Also, up and down still are where they were; rain still falls on your head, not on your chin.
The directions that changed are North and South.
The effect of that is that, from the point of view of the mirror image, East and West seem to have switched sides. The mirror image is looking South, and yet, West is to its left and East to its right.
Look into a mirror with your nose pointing North. Your left hand will point West, and your right hand will point East.
Your mirror image has a nose pointing South, a left hand pointing West (!) and a right hand pointing East (!)
You know it is his left hand pointing West because it moves when you move your left hand. Also, you may wear a ring or have distinctive features on one hand.
You know that left hand is pointing West because you can see the sun set in that direction.
So East and West stayed where they were. Also, up and down still are where they were; rain still falls on your head, not on your chin.
The directions that changed are North and South.
The effect of that is that, from the point of view of the mirror image, East and West seem to have switched sides. The mirror image is looking South, and yet, West is to its left and East to its right.