hi there, the first day of my last period was the 4th of September, had unprotected intercourse on the 21st of September, my cycle is about 30-32 days (been monitoring for the last 6 month), got negative pregnancy test. Tonight just feeling some short (few seconds) sharp pain on my pelvic area. I don't feel the usual cramp like if I was going on my period. Any advice / thought of what is going on with me?