Just had the most horrendous stabbing pain

Hayley • ~IT'S A GIRL!! 💕baby # 2 due May/June 2019~ 💙William Jack 17-08-17 💙
So I've been getting tailbone pain for about a week it's worse when I'm sitting anyway I was just lying down and had like 10 seconds of SHARP pain radiating through my vagina and pelvis. Now I'm terrified. I'm 10 weeks, what could this be?