Did I have a miscarriage?

I'm 22 and I have had a miscarriage before (about 2 years ago), but it was just an insane amount of bleeding and I never saw an embryo. I just got my period a few days ago, but before that I was 3 weeks late and all pregnancy tests said negative. I also took plan b twice that month which I never do. When I got my period, I had a white discharge about the size of a dime and very thick-as tough as chicken skin- and I'm barely bleeding. plan b has never given this effect on me, but since I took it twice maybe that's why? or is it a miscarriage? my mother also had tumors on her tubes and uterus and had to have a historectomy. I'm hoping it isn't cancer related. any ideas?