What does it mean when a woman clots during her monthly cycle.?

I have just went off of my birthcontrol and have a bad cycle, with heavy bleeding and clots that were the size of quarters. Is this normal.What does it mean when a woman clots during her monthly cycle.?
This is perfectly normal. You probably are having heavy periods because the pill actually FORCES you to have a period (during the placebo week). Your body wasn't ovulating, so the lining of the uterus was REALLY thin during the time you were on the pill. Now that you're not using the artificial hormones any longer, your body is trying to rebuild the uterine lining (endometrium).
Yes, I went through that for years before I had my daughter. You are just shedding the tissue lining of your uterus. Nothing to worry about at the moment.
You probably notice the clots most after you have been sitting or lying down. This is blood that has been in the vaginal vault and begun to coagulate.
This is perfectly normal and nothing to worry about.