What Causes Light Bleeding And Severe Cramps During Periods?

Hello Doctor. May be a lengthy question, so I apologize ahead of time if so. I have PCOS and never had regular periods until about 2 yrs ago. Since that time, I have a period every month ( every 28-30 days). I am now 32 yrs old, have never been pregnant, but wondering i could possibly be because i have been extremely exhausted lately, severely bloated, constipated, bad indigestion which i have probably had only ten times in my life until now, headaches every day, some nausea, and have noticed dark rings appearing around my areola's and nipples becoming more prominent and white-tipped. Back to my periods, i usually have one every 28-30 days...well this month it was over a week late, but i did finally have some bleeding for a couple days, but no where near my normal flow. I have also been experiencing some cramping on lower left side, and my usually horrible period cramps did not accompany the couple days of light bleeding i had this month. All that being said, what would you assessment be??