Vehicle Height Question

So I'm still working on my wheel/tire upgrade thing. And in the process of doing this, I've found that my car sits crooked. The drivers side sits about half an inch lower than the passengers side. I measured the edge of the wheel opening at the axle line by holding a level horizontally up against it (leveling it of course), and then placing a yard stick vertically up as close to the wheel as possible. And because the yard stick has levels built into it, I also made sure it was upright that way. I took the measurement where the two met.

On the drivers side, I get 26 3/8", and on the passenger side I get 26 7/8".

I've looked all over the factory service CD and an aftermarket manual I have, and all I can find on this is some specs in millimeters, but neither explains what they mean or where the measuring points are on the car.

I bought the car off the original owner, and to the best of my knowledge, the car has never been wrecked, with the exception of having a tow hitch shoved directly into the front of the car. And it wasn't shoved very far in to begin with. So I don't see where the repair of this would cause the difference.

Can anyone explain how and where to take these measurements and what they should be?

As always, thanks!

Wendell