Honest opinion

On March 3, 2014 I had my Mirena IUD removed to try to conceive but was told by my OB doctor to wait 3 normal cycles  to conceive. I am in a very committed relationship and at this point we are more than ready to conceive. We had unprotected sex Saturday march 15, and for multiple reasons I took a plan b pill that day. I didn't really have any side effects from the pill. On Wednesday march 19 we had unprotected sex again. Then started the best day I started with dark brownish/ red spotting & discharge....that is still present today. Does one think that even though I took the plan b pill that I still could possible be pregnant?