I had my periods on 10th augus and took an i pill on 11th. We did not have sex but as a precautionar

I started bleeding on the 15nd and it is still continuing (today is the 3rd). I have pain in my back and lower abdomen. Not sure when will this stop and whether I will have my normal cycle also. Please advise. Should I go and see a doctor or wait for things to get normal without doing anything.

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