When did I conceive?

Patient: I had sex on 9/14 and the condom broke..my boyfriend was away and came back 9/26 we had unprotected sex I got my period on 9/30 and come oct I missed and now I’m 12 weeks and 4 days preagnant. .please tell me when I likely got pregnant?

Doctor: Hello,It is likely that the bleeding you experienced on 30/9 was not your menstrual period but an implantation bleed and considering your ultrasonological measurement of 12 weeks and 4 days , it is likely that the second intercourse on 26th was the cause of pregnancy.If lmp is take as 30 sept , then definitely the conception didnt occur during septenber but by a repeat intercourse you may have had during october.I hope i have answered your query.regards