That would probably indicate either low or delayed visual-spatial skills--the sort of skills that make you good at things like drawing/painting/sculpture, reading maps, picturing things in your head, mentally rotating or reversing an object, using charts and graphs, doing some kinds of geometry, and having good handwriting.
It wouldn't have to be very low or very delayed, though, because problems with left/right are not an uncommon weakness to have, especially among kids. If you're ambidextrous, it's even worse, because strongly left or right handed people can just imagine reaching for something and conclude that the hand they're using is their dominant hand and therefore that side is left or right. That's how I figured it out.
If it makes you feel any better, I still can't get the hang of "next week", "this week", "this Sunday," "next Sunday," "Sunday after next," etc. I have to ask for the date.