Not Called

So how do I know what I am supposed to do with my life? I hear from my pastor and the things I read that God calls people to be pastors and missionaries. Some people even talk about being called to be a doctor or a teacher. I think I remember my mom saying she felt called to be a mom. But what am I supposed to do with my life? Has God actually called me to be a high school science teacher? Should I be looking for something else? How will I know if and when he does call me or is that just for peo