I've been using tri sprintec for a little over a year now. I rarely miss pills but follow instructions for when you do. I was on my 3rd week of "active" pills and missed day 6 in the morning and had unprotected sex. I took the pill when I remembered that afternoon along with a plan b pill. And continued the pack. When I started the white pills, I missed the 1st day pill that following Monday and took it the next day along with the next pill(2 white pills in one day) and so on... I'm now on day 4 of my white pills and still no period. Could this be due to the fact I missed the 1st white pill, or could I be pregnant ??