I'm about to leave work early. Acute pain in my left side. It feels like it's at the bottom of my pelvic bone. It feels sort of crsmpy but constant and sitting down was unbearable. I've drunk some water, taken Ibuprofen and walked about. It's slightly more bearable but still very painful. I don't typically suffer from menstrual cramps - just a few times a year. Can they be suddenly awful and on one side only or could this be something else?