What Causes Scanty Menstrual Bleeding?

Hi, I am a 35yr old female. I stopped my birth control in January of this year. Started it again in May but only for a month as I have decide I don t need it. Still my menstrual cycle is like clock work every 28 days it will arrive on a Wednesday between 5:30am and 7:00am and last 5 to 7 days. It has been known to come on Tuesday in the same window of time and very rare but maybe once or twice on a Thursday in the same window of time. This time I felt achy like normal on Tuesday assuming it would be there the next day but the aches subsided by that evening and it never arrived Wednesday. It came on Sunday, 4 days late then only lasted about a day and a half before it became light spotting then disappeared completely Wednesday. I have not symptoms really but to be safe I did take a pregnancy test to be sure today, one week from the start of last Sunday s abnormally late short menstrual cycle and it was negative. I ve have some lower abdominal cramping since last evening. Nothing terrible. just uncomfortable. Does this sound like I should be concerned with the late, short cycle and now cramping?