Missed workouts & Charlotte Jeopardy

Been a while, so I'll get to the point. Training took a downturn - and I am hopeful it is nothing serious. After the soreness after my Oct 18th run, I was cautious. Movced my runs around while I was in Philadelphia for much of the week (rested Tues, tempo on Wed, speedwork on Fri). Came close (3 secs/lap off) to my speedwork times and the tempo run was good. Long run was supposed to be 20 last Sunday and finally had a good run. Fresh legs, energy, my mood was good and I was thinking about my upcoming races. After 10 miles or so, felt fine, eventually started getting a little of the usual feelings when you are running for 2+ hours. No problem. All of a sudden, after 15 miles, some pain in my left knee (outer left side). Decided to walk a bit, then the soreness form the week before showed up and I knew that I would not run anymore that day. Walked the next 1/2 mile and ended up with 16 for the day. Not sure where the knee pain came from - but still has me worried. Again, rested Tues and did no speedwork/tempo run this week at all. Instead, ran 5mi Wednesday (after ~4 hours of sleep) and 4 more Thursday - the knee seemed ok, although my legs never had that good feeling -a nagging hamstring, sore toe, weird things to make me not enjoy it too much. But the Spinx Run Fest Half Marathon is Saturday and I am Not going to go after my PR (under 1:47:00) - goal to is get thru it and be able to run Richmond in 2 weeks. Charlotte isn't off the table, but it is in jeopardy.