I know how to look for active effects to see if I am afflicted with anything, and there's no negative status showing up. On my current save, I just leveled up and put a point into the perk that adds decapitation to one handed power attacks (although it doesn't seem to do anything with dual wielded power attacks). My skill is now set from 53 to 15 and I am not using any mods or console cheats. None of my gear is out of the ordinary either.
Sure, I have a previous save that I can load from that's 30 minutes prior, but this is still annoying and I would not have even known my skills had been reset if I had not been looking to spend a perk point. I mean yeah, my damage seemed to be significantly weaker on some enemies, but I simply chalked it up to the weak, weak, weak, super ultra elite, weak, weak scaling issue.