Did I sprain my ankle or possibly break it?

I was running after my 3 year old, and stepped in a hole my dog had dug in the yard. I heard a loud crack as I was going down. I managed to hobble to the house, but had to stop frequently because of pain. I've sprained my ankle before, but never remember hearing it crack. I applied ice, elevated my foot and called the Nurse Line. She said keep doing what im doing and see what tomorrow brings. Do u think sprain or break?