Pain!!!

In no way form or fashion is this a menstral cramp. I have been randomly having pain in my pelvic area. It feels like someone has shoved a knife up in my vagina. The pain starts at the bottom and works it's way up to my uterus in a split second. Then it intensifies for about 30 seconds to a minute. It happens randomly. When I am off my period it happens. I just started my period today and it happened. It hurts so bad it stops me from whatever I am doing. I haven't gone to the doctor because I am still covered by my parents insurance and we are in between changing from personal insurance to my dads work insurance. Any help would be greatly appreciated.