Anyone take the PLAN B pill?

I had taken the morning after pill after sex when I thought I was ovulating. I found out 12 days later I was pregnant. It's hard to tell if I was pregnant before I took the pill and didn't know it or if the plan b didn't work. Either way I'm super nervous about it effecting the pregnancy in a negative way. I already had a miscarriage at the end of November of 2014. I was wandering if anyone had taken the pill before and had a healthy and successful pregnancy and baby??