If you were bleeding for that long after sex I would have just assumed it was your period starting! Sperm can live in you for around 2-5 days (sometimes longer in healthy conditions) but if you were bleeding in that time then most of it would have been washed away by the bleeding. I'm not sure, that;s weird. Are you sure you weren't already pregnant when you had intercourse and that;s why you were bleeding? Sometimes in pregnancy you can bleed after sex.
Hello,
If you had your periods after sex then it is unlikely that you are pregnant. Once pregnancy occurs, cessation of menses occurs.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.