How to tell if my arm is fractured?

okay, im a klutz. today in school, i tripped and fell pretty hard on my forarm. it hurt a lot at first, then it went away, now its back again. it only hurts in 2 places on my arm. by my wrist and inside my elbow. even simple things like opening a door or picking up a binder really hurt. is my arm fractured of badly bruised? i want to know what the people(you) think before i go to the doctor.