I am so saddened to read this. I admire your tranquility through all of this.
In all honesty, I expected a higher result. Last time I remember your PSADT was actually under 3 months. So, by THAT statistic, your PSA is actually slowing down (the velocity of increase is lower).
Using those numbers, your 5.8 would have doubled and doubled again, resulting in a PSA in the low 20's. So, in an attempt to put a positive spin here, the slope of the tangent is decreasing.
Seriously, mention that to your doctor. Your PSADT is lengthening.