I had to download the player count mod which is available online
I entered the game, scanned for memory changes, it found the player count. I then set it to two players, zoned into a new area, killed some mooks, then set it to one player, zoned into another area, then killed more mooks
Happy to say now that this has fixed the glitch after a save, shutting down the mod tool and restarting the game, things are dying at an acceptable rate now and aren't taking 4-6 mags per enemy anymore, before it was around 2-4 mags for a common mook, 7-8 mags for the lowest ranked goliath or 20-30 mags for a Nomad, and this was with a 150 rounds vladof 3000dmg minigun
That and a single round from a common enemy isn't taking out all my shields and half my health with one shot anymore, or riding around in a car its not dead in 6 stray bullet shots.
EDIT1: Additional Info
Everyone keeps asking what is going on with this glitch, so I'll explain
Suddenly, and for no reason, the difficulty in Playthrough 2 spikes astronomically hard, and I mean astronomically hard. Everything starts two shotting you, it takes dozens of clips to down things etc etc.
This is my second toon I've done through playthrough 2, and I couldn't figure out why I was having a ridiculously harder time with Salvador then I was with Axton
So I went back to my Axton toon, and it was just as hard as I remembered, and not as hard as I was experiencing with Salvador, the odd thing was, they were doing near indentical damage, yet it was taking 5-15x longer to kill anything with salvador
Asking around 4chan if anybody had the same issue, somebody eventually talked up after 4+ threads about how there was a glitch in the difficulty system, that how the difficulty slider for when more people join your game was actually causing difficulty to keep adding on levels when people leaved and joined, and not removing them when they left, so if you were solo, difficulty was level 1, three people would join, it would goto difficulty four, they would leave, it would STILL stick at level 4, and more people would join, and it would STILL keep increasing, adding on over and over again.
Case in point. King Mong I was farming him before applying the fix I showed above, using a machinegun car at level 50 it would take around 2-3 minutes to kill him with concentrated gunfire, and he would instantly one shot kill the car if it got hit. After the fix, I can kill him in under 30 seconds, and the car can take 4-6 hits depending on the move he does, its not instantly vaporized by a single one of any of his attacks.
This glitch is what happened too my salvador, and from what I have heard lots of other people playing their salvadors are having the issue pop up, as it rarely happens to other classes as I am told.
Anyways, that is the entire glitch in a nutshell.