CC, when I said rest, I didn't mean for just one day. If you have a problem and keep running on it, you are not giving it time to recover and not finding what the problem is. By keep running on it, you might feel that it's OK, but when you say you felt dreadful and your desperate, that say something different.
I have a training partner who picked up an injury over a year ago, she kept running for a while and has not run a real distance for sometime now, every time she starts again, the same old injury comes back along with a couple of new ones due to changing her running style. She is getting depressed about it and she does not run anywhere near the races and distances that you do.
You may feel bad about missing a few races but think long term, set yourself a target to aim for after a lay off. Hope you get it sorted soon.