tailbone injury?

[mooshoo]

i fell pretty hard on my tailbone a week ago on hard ice while sledding, and it's been bothering me since. when it happened it hurt like crazy and i felt like i would blackout when i stood up. now i have a bruise right in my crack lol
during the day it's like a dull pain that i can ignore mostly, but when i run or jump (during track & field practice) it hurts more and more. and if i'm lying on my back and i roll up into a sitting position, the pain in my tailbone hurts like no other. it feels like my butt is gonna split in half

my mom said i might need to go see a doctor, but i want to avoid that if possible. any suggestions on what to do? will the pain just go away on its own eventually (hopefully soon)?

thanks