Period making me almost pass out?

This morning I got my period and was fine until I stood up. My cramps were bad already and I was experiencing intense shooting pains that I'd never felt before. I got really really hot and I couldn't see at all (my vision went black) and I started shaking and crying. It gave me a bad stomach and then I threw up. Have had this happen to me twice now when starting my period and it lasts almost an hour, the pain is horrific. Has anyone else had this or know what it is?