I have gone through your query and understood the concern. You seem to be suffering from a condition called 'Dysfunctional Uterine Bleeding'. This is commonly seen in your age group when the hormone imbalance
creates menstrual disturbances. Correction is usually done with hormone supplements, weight and general nutritional management. The condition settles down in course of time. Right now, what you need to do is to see a specialist, get the bleeding arrested through styptics and if needed, hormones, get properly investigated and plan further management. Improvement of general condition, healthy diet, healthy weight and regular exercise help a lot. Take care.