Can anyone help me name this movie?

I think it had either Cameron Diaz or Reese Witherspoon as the lead actress (I'm certain that the lead was a blonde woman). All I remember is that the woman meets a guy (or an old friend) and hits it off with him, she goes on a road trip to meet up with him only to find out that he's getting married. The only part of the movie which I actually remember is where she's in the restroom at a truck stop, she leans over in the toilet stall to see why there's a hole in the wall - only to be poked in the eye with a .