Is it possible that I had a miscarriage even after taking plan b?

[llheart]

Hi guys!
I know you've probably heard a thousand stories similar to this, but I could really just use some advice specific to me:) It would make me feel a whole lot better!
So, I never actually had intercourse (I don't like doing that on my period), but my fella accidentally ejaculated ALL over my underwear. I mean, it was soaked. It was the last day of my period and I tend to have super irregular cycles, so I never really know when I'm going to ovulate or anything. I'm a worry wart and absolutely not ready for a baby yet, so I panicked and took plan b onestep three or so days later just to be CERTAIN. I know the chances of getting pregnant were soooooo slim, but taking the pill made me feel better about it. After this, I experienced some sort of bloody discharge, which I heard is normal after taking plan b. A few days later after the bleeding stopped, I started having more symptoms, such as nausea and fatigue. More symptoms continued to accumulate over the next few weeks and before it was over, I was nauseated (especially at night), had fatigue, sore breasts, headaches, and just a general feeling of being unwell. I never bothered to take a pregnancy test because I heard that the pill can mess with the results. After about three or four weeks, what I thought was my period came. It started off as brown discharge, but then turned into very heavy bleeding and severe cramping. The blood was accompanied by huge chunks of dark material. The bleeding lasted for about a week, then slowly disappeared. After it stopped, all of my previously mentioned symptoms ceased. I wouldn't really think anything about it if the "period" or whatever it was hadn't been so strange and the symptoms didn't just stop cold turkey after it. I googled pictures of early miscarriage and it really resembles what I experienced. Any thoughts?? I just want to put my mind at ease and know what really happened. Thanks guys!