Hi babybear,
It does sound like you are pg. If the line is coming up that quickly then it sounds like it. I tested when I was pg with my DD when I was 7 days late and the second line was so faint I had to get three people to look at it before I believed that I wasn't just imagining it. Symptoms sound like you are pg too but that's pretty early for symptoms to come on. I've never heard of diarrhoea reducing the effectiveness of the pill. Sorry. Congratulations!!!!!