How do you know if you sprained your ankle?

I tripped on the sidewalk and for the rest of the day my ankle hurt horribly. It’s like a growing pain in my ankle but much worse and when I walk, it feels like I’m pulling a muscle in my shin. Do you know what I mean? It feels like my muscle is stretching apart in an uncomfortable way. It aches like crazy!!! Have I sprained my ankle? If not, what have I done to my ankle? Please HELP!!!!!