How come my foot is numb?

Well my foot has been numb for 2 days in a row now. And it happened after I was rollerskating for 2 hours with skates that were a little big for my feet. Then about 30 minutes after skating I went biking outside for a bit and then played tether ball. I fell while skating about twice. Once crashing into someone. My foot is still numb after all that. My mother told me I could of popped a nerve. The only numb part of my foot is my left big toe. Not a very proper word for my big toe but i have no other idea what to call it. Anyway why is my big toe still numb?