Severe lower back pain/pelvic pain during period?

Okay so us ladies know that when the period comes it sucks! My usualy period is extremely heavy bleeding and unbearable cramping from the uterus contracting. This period has been one for the record books and im unsure if i should be concerned enough to go to the doctor. To start my period was a week late. The few days before my period which never has happened before i started to get extreme back pain in the lower back and pelvic regions. This has never happened to me before. I'm 24 and have had my period since ive been 12. I got my period yesterday afternoon and since then my back pelvic pain hasnt lessoned. My cramps were extremely bad but i took midol and they lessened. Ive also noticed twinges like twinges of pain in my lower abdomen where my lady parts would be. I cant explain the pain but thats not a first for the past few months that seems to happen all through the month. One thing i also noticed was once or twice i had this month and it actually hurt like mive cramping happened. Do i have anything to worry about. Is this normal ? Im not sure what to do please help.