Periods on Tri-Sprintec?

Brooke

This is my first month on Tri-Sprintec. In the second week I had sex, he pulled out. In the third week I had one incidence of brown spotting. I'm now on day 3 of the placebos and still have no period. I always take my pill on time and everyday. I'm not sure if I should be concerned that I'm pregnant or if it's just due to my body adjusting to the hormones. Anyone have advice or similar experience?