Hi im 21yrs old and this is the third day that my tailbone hurts.?

i can't sleep on my back it hurts, and (this is kinda gross) but i've tried to feel for my coccyx and u can feel a bump on my left butt cheek right at the top. this has happened before right before my period and it goes away after a couple of days, but this time it just feels with too much pain... help :/