Fly me to the moon...

This was not a good morning.  I woke up to my alarm clock, but then fell back asleep.  I woke up again later and was late getting out the door to meet Sasha.  I couldn't find my keys and had to borrow my wife's set.  I met Sasha and Jeff, but I wasn't sure how many I could do with my knee giving my troubles.  It felt okay for the first half mile or so, but then it started hurting again.  I thought about turning around after 2 and probably should have, but I kept going until 3.  There were a couple of times when it felt like my knee was going to give out.  It was a sharp pain on the side of my knee that caused pain up and down my leg.  Strangely though the knee felt a little better after each time.  I turned around at 3 and headed back.  It was doing okay until I hit the uphill spiral after the tunnel under Geneva Rd.  It really hurt to go up that.  I continued on to the 5 mile mark and then stopped.  I tried to run a little bit farther, but it hurt too bad.  I ended up walking back home from that point.  I've never done that before.  I've never had to cut a workout short and walk home.  I've never really had an injury like this, and I don't like it.  I'm not sure what the problem is, but it started after my day back on the 30th.  I had some pain after my run that day.  Perhaps it was too much or too fast after 10 days off.  I wouldn't think so, but I know my shoes aren't helping the situation.  I need a new pair.  I'll see how it feels tomorrow, but I don't think I will run on it.  I spent most of the day limping around on it.