First off... Ginny - sorry to hear that you were unable to run today. Take is easy and run in the next one. I really hope you can get better soon! If you are worried about losing some endurance - do things that will allow you to keep active and not aggrevate it. Swimming, elliptical, light weights, etc - or take a class. Just an idea.
As for me, today was a blast. I showed up at the Chambersburg 1/2 marathon and helped with the registration. In talking with one of the guys (he could not run due to rolling his ankle in Disney in January), he mentioned he was heading to the first turn for the start of the race to control traffic. I offered to go with him since I had nothing scheduled. While walking to the point, he mentioned that he wanted to head out to the 1st water stop just over the 2 mile mark.
After the runners passed us, we set out at a jog ( `10 min mile) and started passing runners. It was fun talking with people as we run with no expectation on the race since, realistically, we were volunteers. We avoided the photo spots making sure they knew we were not running in the race. I remember passing 2 ladies and hearing them comment on my "running gear" - jeans, old pair of running shoes and a regular jacket with a ball cap. We had to turn around and let them know we were volunteers!
After a few min. break, we turned around and went back to our post - getting there about 10 min before the leaders arrived. I ended up waiting until one of the last guys we talked to on the way out was coming back and I ran back with him to the finish. I did not realize it, but he thanked me for helping him finish the race. He was getting to the point of having to walk the rest of the way when I joined him. He ran the final section and finished strong.
Over all , we had a good time and I now realize that there are a lot of stupid drivers out there. I cannot believe how many idiots there were driving - trying to "beat" the runner , flipping us the bird for hold them up, getting pi**ed over us yelling at them to slow down (they came close to hitting someone), etc.
I only ran 4 miles today, but I feel like I ran the entire 13.1 
October Baltimore Running Festival Marathon (also the 2nd part of the MD Double challenge)