hey, you said you're coming back after a long break, right? That means your form will be less than perfect.
My suggestion: Look to see if your knees are sliding forward at the bottom of your squat. The knee angle should be established in the first third of the movement. After that, you should be 'sitting back.' You don't want your knees to slide forward when you're in the hole. Does that make sense?
This is from Mark Rippetoe:
Video of your squat form would help.
Also, it is only fair to note, 225lbs for 6 means you're a strong squatter. Hats off.