What Causes Prolonged Periods Along With Severe Abdominal Cramps?

I had my period from feb 8-16 very long but while on it I was sexually active for couple of the days now it s the 23 Ed I was feeling fine but I woke up this morning with this cramp/pain on my left side and onto my abdominal. idon t know if im freaking myself out , if it has anything to do with it at all .