The "number hit me harder than the depth did" part... I get what you mean but the depth can mess with you too if you go deep enough, especially on repeat dives. 500 in the Gulf is a ton of bottom time though, were most of those shallow reef stuff or did you get into some deeper rig runs? Either way that's a serious count, most people never come close.
I read a DAN piece a while back about how the deep stuff stacks up on your body over time, not just the single dive. It said repetitive deep profiles are what really get people, the little hits add up. Most of my 500 were shallow, lots of 60 to 100 foot reef and some spearfishing, but I did maybe 40 or so rig runs in the 200 to 300 range. The deep ones are a different animal, you feel the hang on the way up even when you're doing everything right.