I can't even walk

I can barely walk. The pain in my legs is that bad. And I didn't even do anything recently to make it like this. The only thing I can think of is that the snow has made it really, really cold so maybe that's what's causing my legs to be like this. But it's hell. My room is at the top of the stairs, and I can barely take them. Even walking to the bathroom is hard! This is ridiculous!