Left side of 2001 M Coupe 3/8 of an inch lower than right?

Hi everyone,

While washing the car today, I noticed that the left (driver side) of my car is about 3/8 to .5 of an inch lower than the right. it is the same at both the front and the right wheel. It is not a difference in tire pressure, as the difference is in the gap between the fender and the top of the tire. The vehicle is completely stock, and has never been in a wreck.

What could possibly cause this? The car only has 37,500 miles on it. My only thought is that there has rarely ever been a person in the passenger seat, but I weigh 170 and I can't believe that the little bit of driving I do in it every year would drop the side of the car that much.

Any thoughts, suggestions, or ideas what might be causing this?