I hit just below my left ankle a week ago on a metal table. it is a bit swollen and bruised and really hurts to touch and is numb. what is this?

Contusion on nerve: Most likely just a contusion . Elevate , ice and rest for a few days. Will slowly resolve. If however, you hit with great force, heard/felt a "snap" and are unable to walkon it an xray is in order to rule out a more severe injury like a fracture. You probable bruise the nerve as well.

Nerve?: Possible nerve damage from the injury and should at least get x-ray to make sure no fracture.