Tailbone pain

I'm 27 & 1 and for the past few days I've had cracking and intense pain in the tailbone.

It started when I was sat a certain way for too long but it's now constant and gets worse when rolling over at night and when going from standing to sitting (vice versa)

I can't see my midwife or GP about it until Tuesday and I'm away but does anyone have any advice on how to deal with the pain or what's causing it?

I regularly use my exercise ball and sleep on my left side.