hi. i got my period july 21 ended the 25. i had unprotected sex the 27 took plan b the 30. then got my period the 3 aug. ended around the 9. had sex the 10 through the 15. then started spoting with light bleeding then the 18 had heavier bleeding the 19 no bleeding and today the 20 light spoting. am i pregnant or is the plan b affecting me?