Well, I'm officially aggravated about my race.
As I mentioned, I got sick that week before but really didn't feel THAT bad and had no idea it would affect me that much. Been thinking about it since the race and wondering what else could have happened. But, on top of that, this is the first race where I've tried to keep up with running afterward and not completely shutting it down. I only ran once that week right after, but since then I've gotten at least 3 runs/week. Nothing crazy, but did 12/11/17 miles the previous 3 weeks. Certainly nothing to build any fitness but the hope to at least not lose too much.
Well, I've been getting frustrated because my runs have felt horrible. My HR has been much higher than usual, it hasn't felt good, and I basically felt like I did when I started training months ago. It wasn't making sense because I shouldn't have tanked my fitness that much that fast. My VO2 max plummeted to pre-training numbers as well so Garmin agreed. I was running in the high 10's with HRs in the 150's and even 160's. And this was all in good weather.
Then, for whatever reason, the last 3 runs have felt "normal" again. Just did over 4 miles and my AHR was 140 and I was in the 130's most of the time while running in the low 10's. Certainly nothing I've done training/running wise to expect any sort of bump, and definitely not that drastic of an improvement.
So, at this point, I'm pretty convinced that whatever I caught really did a number on my fitness and basically wrecked my race. I can't think there's anything else that would explain the sudden turnaround.