Pop goes the Angel???

I took the last few days off as part of my taper for the Angel. This morning I decided to do a easy pace 6 miler just to get the legs moving. I was about 2 miles into the run when I heard and felt a pop in the lower back that had enough force to knock me to the ground with a spasm in my right leg. After I stood up I had a shooting pain that went from my gluts to ankle. My guess is that I tweaked the Sciatic Nerve. I loosely blame the posture and lower back exercise the trainer has me doing. Anyway, I hope that this does not screw up my plans to run the 50 miler this weekend. I am going to do a 4-6 mile walk in the morning followed by a sauna and soak in the hot tub to see if this loosens thing up a bit.