What Causes Light Spotting Abdominal Pain And Cramps?

My period started yesterday and it s very low blood almost nothing but I had terrible cramps the entire day yesterday. I thought today the flow would have been more but it s the same. The third week in December I had sex with my now boyfriend and it s been painful every time almost to the point where I m near tears I would feel a striking pain in my lower abdomen to the point where I ve discontinued having physical sex with him being afraid of the pain. Ever since that night my cycles have been off, late by a week or more, early by a week, this was the first time it has came on schedule since my last cycle in December. The only difference being this cycle came with major cramping and it s almost as if my period isn t on? Can this indicate anything harmful or serious before I rush to my doctor in panic??!!