On the first day of my period I got sever lower back pains and lower abdomen pains. I then got up to get a pain killer, but my legs were like jelly and shaking. anyways I went into the other room to get a painkiller and completely blacked out. but I was still standing up straight and fully conscience, I just went completely blind, could not see anything, then I vomited. What could this be? This is not a regular occurence, and I am only 17