I have tried to research this myself because when I explained my situation to my local clinic, it seemed like it was a non issue. Tonight was just the third time it has happened but it has been the worst. A little bit after having sex with my long term boyfriend I started to feel slight lower abdominal pain. It gradually grew to feeling severally overheated, worst lower abdominal pain (and I ve gone through cervical treatments-LEAP- almost 2 years ago and those and cramps didn t even measure to this), nauseated but only enough to make it more uncomfortable...I felt like I was going to die or need the hospital. I crawled to the bathroom as my boyfriend got a fan going and ice water. Maybe 5 minutes later I was back to normal.