Scary! Glad it didn't result in anything he did at daycare or it would be much more stressful for you! Glad to hear he's okay. My son could not walk for three days last spring...his legs hurt to the point that he had to crawl to get around (he was 4 at the time). It was really scary, but two doctor's both said it was just shin splints (he is pretty active and loves jumping off of things). Maybe it is something like this?