If your EQ hasn’t changed, then you are probably doing too much. If you were in the zone, your EQ should have IMPROVED!
There are guys like yourself that have pretty strong dicks, so it takes a lot to cause decreased EQ , yet shortening is a definite neg PI. I suggest take a week off, see if your length returns to normal. Also pay attention to your EQ, if it improves during the layoff, it is a strong indicator of having been doing too much.
In general, I believe most shortening or shrinking is due to the smooth muscle contracting from too much trauma, rarely contraction of the connective tissues unless you are using really high forces. The smooth muscle will recover fairly quickly and size will return during the layoff.
If your EQ improves during the layoff, then when you restart your routine, make sure you can regain your best EQ within at least one day layoff from PE. If it takes more than that you might consider decreasing your workout, or you will have to go to one on and two off.
The point is you must return to excellent EQ before you hit it again or you will begin to go backward. Shrinkage is a definite neg PI and indicates you are doing too much. (make sure you are accurate with your measurement, I recommend bpfl at 90 degrees straight out…bpel is too subject to EQ to be dependable)
I suggest when you begin again, either cut your work out in half or go to one on one off, or two off. The real trick is to get improved EQ before you start doing too much, because then you have a real reference point as to where you are at on a day to day basis.
Once you get good at reading your EQ, you will never get too far off track, because you will see right away if you need more rest before you hit it again.
I suggest reading my EQ thread linked at the bottom of this post if you haven’t.