I lost all feeling in my legs.
Seriously, if I thought the second lesson was any at all a pain in the ass, if I thought the focus and determination I needed then was already a bit too much - hell, that's nothing compared to what came after.
From the way I was trying to place one foot over the other, my entire lower half may as well be one of those flailing inflatable balloon guys you'd see in shopping malls and the likes, and if the hard stumbles I just took were any indicator of anything, then I clearly had a puncture hole somewhere cause I was deflating fast.
Furthest I got was just barely past the doorway and even then if it weren't for the amazing breakthrough that was concrete walls, I'd have nothing to lean on to save me from another painful fall.
That's another thing about muscles - when they get sore, they really get sore. Christ almighty...