i understand this is older thread, but you really got be patient with a sprained ankle. it is excruciatingly painful when it happens, and swells like a grapefuirt after injury. it will take at least a couple months to heal completely. it is slower to heal than upper body injuries becuase it gets less blood.
after the injury you may be walking and cave in without warnign. if you play sports use a swedish brace till you are [positive it has healed completely. this is a sort of like a leather sock with wired reinforcement. you lace it up like a boot and put your shoe over it. its a real pain but beats reinjuring it!
you doc may want an xray to make sure there are no broken bones.