What injury could this be?

I am a ballet student. Plie, or bending of the knees in ballet, is done throughout the entire class. Though this is so, my ankle has been bothering me lately. When I bend my knees, there is a lot of clicking around in my ankle and it soon restricts motion so I can go no further down. It clicks, and its painful all in that little dip part on the outside of my left ankle. Is this anything serious? What should I do? I've been icing it!