Hi Electron!

Welcome to the forum!
Sorry you are having difficulties!
Many of the meds used in treating neuropathic pain have the potential for cognitive side-effects. It's really trial and error, as far as finding the most helpful med(s) and the best dose for each person.
I am ultra-sensitive to meds and really struggle terribly in trying to tolerate most of them. Some of them have caused additional neuropathy for me.
I was able to really catch the trends with meds when I had started to keep a simple diary. The diary had also helped me to show the trends to my neurologist(s).
MrsD gives great advice! I would start with one med and slowly taper down or off of it, too. Gabapentin is notorious for causing a slowing in cognitive function.
Hope to see you around!
Take care!
~DejaVu