I have chugged hundreds of bottles of robitussin, popped boytaur handfuls of rogogels, drank countless gallons of wine and spirits, eaten enough benzos to take down a Persian war elephant battalion, smoked weed until my lungs bled and still kept smoking, inhaled volatile chemicals in depths of depression to self-mutilate, and encountered two concussions. I am far more focused now than I ever was. Do not mistake age, and the ego-fuck that comes with realizing that your mom is wrong--you are not the smartest person in the world--for permanent loss of some frontal brain function. In fact, sometimes you will be proven wrong by people that you would laugh at.
Your brain is resilient. Read this article, and learn patience. You will recover from your HPPD.
http://en.wikipedia.org/wiki/Neuroplasticity