Ended period 9/24 and my bf ejaculated inside of me on 9/25, 9/26 and 9/27. took plan b on 9/27 and my period is 6 days late now could i b pregnant?

Pregnancy unlikely: Although pregnancy is unlikely, it is NOT impossible, so if you are, or will be late with your period have a pregnancy test dona.

Yes: Pregnancy has been documented from unprotected sex on any day of a woman's cycle including during menses. Plan B is not 100% effective in stopping pregnancy. Wait a while and do some OTC urine pregnancy tests.They are more often falsely negative early in pregnancy but once they turn positive the test is valid.