What Causes Spotting With Abdominal Pain And Nausea?

I started my period 10 days ago, but I am still spotting every day which is unusual for me, I have had pain in my right lower abdomen for 4 days (crampy and stabbing), and feel nauseous. Also felt dizzy and just 'strange'. Negative urine pregnancy test this morning. Also I ovulated according to the kit today - which would mean I will be on a 22 day cycle this month - I am usually 30 days. What is going on?