I had my period july13 and july27 i had unprotected sex now i got my period aug4 but it was light but got heavy it last for 4 days now i miss my period it was aug4 help?

Take: A pregnancy test, it is not unusual to have a period or two in the beginning, usually lighter and or shorter, when pregnant..

Hard to know: Your menstrual history is very difficult to evaluate, but certainly the timing of unprotected sex is worrisome. You might have considered Plan B or something similar at time time. The fact that you had a period, light, got heavy means you did not conceive or you did conceive and had a very early miscarriage. If you are going to be sexually active you must be sexually responsible. Contraception!