Hi doc am 27 yrs old I had unprotected sex on 13 dec2012 I immediately took a combined contraceptive pills on the 2nd day after sex I continue for about 10 days and stopped before about 5 days.
Now am suffering from lower abdominal pain, slight diarrhea and gasses .my period is late about 16 days and am not sexually active.I did pregnancy test yesterday and was negative,
Should I take mifepristone followed by 4 misoprostol tabs to be in the safe side?

Not sure what pills you were taking, was it a "morning after" type pill or set of pills, that are used to stop or try to stop fertilization of the egg.

What you are talking about is basically a abortion pill, used in some areas and requiring doctor in most areas.

You don't even know you are pregnant. And will not for a few more weeks, you are testing way to early.
And of course your periods are off, that is the medication you were taking