gah!

I did my usual 2.3 mile route this morning and my knee is killing me. I did too much too fast. I iced it all morning here at work and took some advil. The advil made it better which makes me think it's muscular, which is good. I guess I had better take tomorrow off... or just walk, no running. What do you guys think? Which is better, taking the day off, or walking?