WOW! Okay I see what the issue is. I died from a creeper while wearing some armor. Then I went back down, picked everything up, and ran into a skeleton. While wearing No armor, each arrow only did 1.5 hearts of damage, but after donning my mix-matched armor, I was suddenly nailed with over 5 hearts of damage from the arrow.
I respawned, and made the exact same armor mix-match as I had before. (Iron chest, Bronze Legs, Iron boots) and found that all mobs were then doing normal damage to me.
So, the armor I was wearing originally was glitched from the update I guess? But now there's a new problem it seems.
Even if I'm wearing newly made armor, (Bronze, Iron, or both, it doesn't matter) The mob's damage is still affecting me as if I wasn't wearing any armor at all.
Suggestions? (Difficulty is set to 2 now)