It definitely sounds like vertigo to me - I'm no expert but I have dealt with vertigo while diving before.
In my case it was a cold water lake dive near a dam, second dive of the day. I was fine until we got close (not dangerously close) to the turbines near the base of the dam - at that point some combination of dropping down with less than 1 foot of visibility, the sound of the turbines, and a thermocline just knocked my brain silly. I remember looking at my computer and seeing the depth just dropping and not quite understanding why - I hit another thermocline and was like nope! I finned up until I found a ridge to sit on around 70 feet, where I proceeded to just stand awkwardly while trying to focus my brain. The visibility opened up a tiny bit and I was able to get the attention of my dive buddy. To this day I have strange memories of swimming around in mustard yellow water and sitting on a huge concrete ledge (photos indicate it was actually a rock, not a lego-shaped block like my brain thinks it was). I remember being afraid my buddy would never find me and I'd get sucked through the turbines in the dam (despite logically knowing I was nowhere near a dangerous area).
I recovered enough to get another diver untangled from his spool/DSMB and get the DSMB untangled from an overhead dock but it was a nauseating task.
By the time we got out, I was so dizzy and sick I didn't care about my dignity or my kit and sort of half-dragged myself up the shore trying not to puke.
I haven't had it happen since, but it was definitely a unique experience. I remember being thoroughly disoriented to the point where I almost forgot where I was even diving. It set off a massive surge of anxiety while I was standing on the 'concrete block' which didn't calm down until my buddy came into view.
The only lasting issue I seem to have is I am now very prone to seasickness during surface swims or waiting for pickup - that was never a problem before but is almost debilitating now (to the point where sometimes I can't even walk straight after getting out during shore dives and tend to stumble off to puke in a bush).