Does Spotting After Unprotected Sex Indicate Pregnancy?

Hello doctor.... Last month i got my periods 10 days late.... Dan i had unprotected sex 20th day from first day of my periods.... And than on 24th day.. It was very painfull penetration(missionary position) ... And as i got up a bit of blood flow out... But enough for being noticed.... Am i suppose to have any problem? What are the possible chances... Shall i use preganews now?? Plz help... Thank you