Started my birth control sugar pills sun., i usually get my period wed. i got it mon. it's darker and dryish. i was on antibiotic tinidazole.pregnant?

If it was actual: period you shouldn't be pregnant - BUT if ever in doubt - can always take a home pregnancy test. Take care.

Unlikely: It's unlikely you are pregnant if you took all your birth control pills. However, antibiotics can reduce effectiveness of the pill, so it is at least theoretically possible - Regardless of the circumstances, if you are concerned you might be pregnant, take a home pregnancy test! they are inexpensive and very sensitive (will be positive by the time of your missed period).