The focus was primarily on backstroke drills, and backstroke is not my strongest stroke. In fact, it ranks right near butterfly (but slightly better). The primary stuff was 200m of 12-1-12 (kick 12 times, 1 stroke, kick 12 times on the other side) and 200m of 6-3-6 (kick 6 times, 3 strokes, and kick 6 times on the other side). My legs were pretty much toast after that. And my shoulders were too, after adding this onto the 300m backstroke pull and all the backstroke in the "warmup."
But amidst all the struggling, the focus and HTFU paid off. My kick got smoother, my pull firmer. My hips and legs started to rise near the surface rather than drag towards the bottom. I became more comfortable with the water "so close" to my face - it's funny that I'm more comfortable with my face in the water than out! Things started to come together.
And at the end I was refreshingly beat. I slept like a rock last night, and right now I'm rather tired and achy in the back and legs. I know I'm stronger from all that work last night.
Now if I could just get that butterfly down. ;)