When I went to see "Mother", I had the same experience. If it were not for the fact that the movie was so beyond brilliant, I would have left over the sound quality in the theater. It was ear shattering noise. Maybe that was the point during some of the later scenes of war, but it was hard to handle. I was so enticed by the visuals and the theme that I let the noise take a back seat.
It is not you, the sound really is getting worse