What Did I Do...

Ei yi yi, what did I do?  After running the Papillion HM marathon yesterday, I was only 16 seconds off my PR pace from two weeks ago.  Immediately after the race, I felt fine, but throughout the day yesterday, my left knee continued to progressively get worse, and worse, and worse.  Today, it hurts so bad, I just don't understand it.  I can barely walk, can't go up or down stairs, and it hurts to bend my knee.  I think the hills, and running extra hard near the end of the race really may have done me in.  I decided to do some light swimming today at the gym, nothing strenuous, only for the fact that I can't really do anything else.  Ouch, my knee hurts.