It’s probably not as much as it seems. Most women lose about 3-4 tablespoons of blood each period.

Having a heavy period can depend on how it differs from your usual cycle. If it is progressively getting more heavy, it could be due to a Uterine fibroid, a polyp or other structural problems. 

If it surpasses the normal amount by significantly, you should consult a doctor immediately. Losing a large amount of blood can be due to other serious causes, the most severe one being a miscarriage. It can also occur if there has been any trauma in the genital tract. If it has been happening very frequently, it can result in Anemia and lead to fatigue and dizziness. 

If you use more than 10 pads or tampons a day, or are soaking through a tampon or pad every hour, talk to your doctor.