I'm not exactly sure why I was able to sail one good race and follow it with two bad races. They weren't that different, although the mode of sailing in the waves changed a tiny bit I think.
In the first race I started near the boat end, found a clear lane heading right, and sailed fast. I was focusing hard on constant angle of heel and found a nice slow rhythm of leaning against the pressure in the sail as I sailed up a wave, then leaning in to ride the bow down the back side. I took one or two little hitches in when I felt knocked on port, but otherwise went to lay line from pretty far out because I felt I was in good pressure in my corner. I over stood a little bit, but rounded in 4th and managed to hold on to it. Since the waves were pushing us pretty hard to the right downwind, and it was very light wind, I stayed hard by the lee on starboard on the down winds and did not get passed.
In the second race, I tried to do the same thing, but finding a clear lane was much harder, and I don't think I had the same speed. Downwind I was losing a bit here and there and I'm not sure why. I never found the same smooth rhythm either upwind or downwind for the rest of the day. I'm sure it didn't help that when I felt uncertain about what the fastest mode was, I spent time trying different things to find it.