Sharp pinching pains in lower stomach/uterus area???

Im in school amd ive been fine all morning, but then in my second hour i stood up to take my hoodie off and as soon as i stood up i got a sharp pinching pain right above my pelvic bone. It hurts to walk, it hurts to stand or really move in general without the pinching cramps. My period isnt due for a little less than 2 weeks, any ideas what it could be? Anything will help :)