What Causes Prolonged Bleeding After Having Intercourse During Menstruation?

Hi, I am 22 years old. I had unprotected sex with my husband on 5th april and my period was running that time. I took an i-pill during period. the next day it stopped bleeding. But from the next day it again started bleeding heavily and till now it is bleeding in heavy flow. Usually my period stays hardly 4-5 days. But this time it is running for 8 days with heavy flow. Please tell me what to do
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