Pregnancy after abortion and plan B pill

I had an abortion in the beg. of december. Three weeks later my fiancee and I ended up having an in heated moment on christmas and had unprotected sex. I did take the plan b pill within 12 hours of having sex. Now second week of in the new year. its been almost 6 weeks after my abortion. I'm wondering if I could be pregnant again and since I found out at 9 weeks the last time I was pregnant because I had no signs. Just thought I was late due to stress. I"m scared again I could be pregnant. A day ago I had brown spotting and clear discharge and I can't remember if this was one of the signs they told me about.