Is this normal ?

I know what it feels like to be sore and hurt from excessive exercise being in the military, I know what it feels like the next few days after doing squats but this isn't what I'm feeling at all, every time I sit, or try to sit up straight my tailbone hurt, well at least that's what it feels like. It's been 2 weeks now that I have to sit slow in order for it not to hurt too bad, it's more uncomfortable than anything. I know for a fact it's not excercise what do you guys think ?