It sounds like you may have either had a serious sprain or broken some of those tiny bones that are in the foot. You definitely should see your doctor and he will probably order an X-ray. That sounds painful. I twisted mine before by missing a step, and the hospital put on a cast and this relieved the pressure on my foot and made it feel a lot better. Mine was just a sprain.
I have repeatedly sprained my right foot and walk with a very slight limp. However, some years ago I could not put any pressure on my right heel and I went to an Osteopath who checked my sputum, my hair, nails, etc. and told me I was a "walking pillar of salt". Anyway, long story short, he put me on a mineral supplement and I was greatly surprised to find that in less than a week I could step on my heel without pain. ~ I agree with Ozmee that you should see a doctor to make sure you didn't break anything. The cast sounds like a good idea for now. ~ You might try some bone building supplements also such as Ipriflavone, Calcium and D3.