"That snake" is not chasing you. You might seem threatening to that snake. Also, remember that, I know this might sound cliche but, the snake is probably more afraid of you than you are afraid of it. With animals out in the wild, one scary thing, is like a death threat. They don't know if "that scary thing" in front of them is going to kill them. At least you can go to a hospital if you are hurt, once an animal is hurt, they will probably die there.
The snake is probably trying to get to it's den. If it is going in any direction, including your's, that is probably the direction of the den they are trying to get to. Snakes will not chase after you on purpose, it is just that they are trying to get away.
