thank you for your question if you had unprotected sex one day after your period there are very low chance to be pregnant.the bleeding after unprotected intercourse dosnt mean pregnancy.i dont kwou how old are you, has happend this before ,your partner has other partners before, this bleding is asociatet with pain or not.in general i can say it may be caused by a irritation during intercourse may be coused by a infection or hormonal disorder if you continues to have sppoting take contact with a doctor or write here again to explain how will we procide and which examinations we need to do.till there is important to have protect sex.write again for every thing you need to know