i am use to having my period for 5 days but for last month and this period im going into my 8 day and i am having some heavy and painful blood clots. what can be the cause of this

Are you sexually active? Could you be having a miscarriage?

im in the same boat as you...i get really painfull, blood clotty periods that last 9 days sometimes...i went to the doctor, had a blood test and he said i was anemic, and this was causing the increased pain and blood clots.

im now taking medication for the anemia.....

you should go to the Nurse and get a blood test done ASAP.

I would see a Gynecologist about this, as several things may be the cause. In my own experience, I was found to have Fibroid Tumors and that was the cause of my heavy and painful menstrual cycles. They are not cancerous, and are fairly common in women over 35. They can however be very bothersome, and sometimes can cause some bleeding after intercourse as well. This is not usually harmful but can lead to anemia so that should be watched as well. Be sure to rule out infections as they can be harmful if left untreated.