I have been on birth control pills for three and a half years. I am usually very good about taking my pills but the past few months I had a very hectic schedule and sometimes I would end up taking the pill in the afternoon instead of 9:00am. During the third week of my birth control pills this month I took my pill late and then few days later I had sex. The condom broke and we did not notice until the deed was done. As I was late taking pills, I decided to take plan b. Within two hours I took plan b and did not feel anything besides fatigue. A week later I got my period as I should have, but it is very light. On the second day of my period i took a pregnancy test, which came back negative. Should I take a blood test to make sure, or should I be fine and the light period is due to the plan B?