What Causes Cramps And Delay In Periods?

Hi...my periods have always been regular, and this month it came five days late (today). I had been having period cramping and acne so I was a little confused. I took a pregnancy test the second day I was late and it came out negative. Now that I've gotten my period it seems to have a slight orange tint to it and is not as heavy as it normally is initi any thoughts?