swelling after sex

Please help!! Me and my boyfriend have been together six months and have had sex a number of time but all of a sudden, today after sex my right labia majora became really swollen (almost like it was cramping up) and hurts to touch. I don't have any other symptoms, just swelling and pain. I've been icing it since but I'm really nervous and don't know what to do. Anyone have any advice/help?