Being sick is no fun. Going from 60-plus miles per week to ten is even less fun. Running twice in a week and then stopping because the body needs time to heal is a decision only based on experience.
I say this because I am in, hopefully, what is the last 24 hours of this year's annual head cold. It started last Tuesday, Jan. 27 with a sore throat and congestion. The sore throat left the following Thursday/Friday following a period of daytime when my voice was a full octave lower. And then the gunk sunk to my lungs and I started a nice productive cough that is still with me, nine-or-so days later.
I've taken seven zero days in the past 12 days, almost equal to the nine I have taken from just before I got sick back to Oct. 19, 2014. Seven-day and three-week rolling averages are paltry. And I need to once again adjust my peak weekly base mileage, dropping out the two final weeks of base period - current set for 80 miles - and replace them with 70 mile weeks. I'll still probably keep the peak at 80 for in-season training - I see no worry to cycling up to that high mileage a small handful of times throughout out the year.
The weirdest effect of being sick is that my motivation to run has been all-but nonexistent, like my body is telling me to not go run. For the most part I have listened to it. Morning runs are basically not happening. Evening runs are affected by how I managed through the day. And weekend long runs just didn't work.
And so it goes. Adjust training goals on the fly without changing racing goals. Just adapt to meet those racing goals.