Well I did feel a bit better today, though after lunch I had the same nagging headache I had on Saturday. This time I did something I don't do that often, I took some over the counter medication, it took the edge off.
So my run this afternoon was definitely better, though that may have something to do with the meds. I have to say though I have been running the same distances this week, the quality of running has been better, so that is encouraging.