In reply to Tommyads:
It's not unusual. I once fell off a boulder problem at Burbage, and rolled my ankle over on a rock. It hurt, but I strapped it up a bit, did my shoe up tighter and carried on climbing for a while. I then drove home and made my dinner. It was only when I got up from the table that I realised that I just couldn't place any weight on my foot at all. It was absolute agony. I ended up going to A&E, where it was x-rayed. Not broken but a fairly bad sprain. Not much I could do but wait for it to heal and take ibuprofen.
However, it might be worth getting it checked out, as my girlfriend has done something similar and ended up in plaster for 6 weeks for a broken metatarsal.