My dumb foot

As I posted earlier, I've been training for the Rex Lee run coming up this Saturday. I had been doing really well and could almost run the entire 3.1 miles without resting. Well late last week I got home from my run and within about an hour my left foot hurt so bad I could barely walk on it. I figured I had probably just sprained it and rested a few days to let it heal. This last Monday I decided to get out and run again and ended up hurting my foot even more, to the point that I had to walk on my tiptoe to get around. I went to the doctor yesterday to get it checked out and they did an x-ray but couldn't tell for sure if I had a stress fracture. The doctor basically told me that I need to rest my foot for several weeks and ease back into running next month. At that point if my foot is still hurting I need to go back in so they can do some tests. I'm so frustrated! I was really looking forward to my first race of the season and now I can't even walk it. Urg... Oh well, there will be other races I guess.