My period started jul 4 th 2014. i had sex on 16 th and took plan b on 17 th. i had sex again on 20 th. my next period is due on 29 th. am i pregnant?

Too soon to tell: If you miss your period by 4-5 days, do a home pregnancy test. Use first morning urine and follow the instructions for the test carefully.

Too early to tell: i doubt that you are pregnant. assuming you are concerned about the encounter on 7/20 where you did not take plan B. it is simply too soon to tell. as you have not yet missed your period. i would start with a urine pregnancy test if your period doesn't come in a couple of days.