Squat struggles

The last month I've been struggling something horrible with my squats. On Friday I was scheduled to do a set of 3 at 395 pounds. I could only get 2 reps at 375. All of my lifts have increased except my squat. Squat. This is kind of shocking for me.  Squats always been my strength. I've never struggled with squats before. But at least everything else is still gaining.