What Just Happened...

So I went to the bathroom to pee, when I wiped there was this brown looking clot.. I'm thinking WTF, I smelled it (I'm weird) it wasn't smelly & it didn't smell like period blood, but I didn't recognize the smell either. So I wiped again, & a little more, so I wiped a third time & this time it was kinda red, but again, not a deep red like period blood. AF isn't due until the 13th.. I've taken 2 pregnancy test (clear blue) & both BFN.. My nipples are sore & I have mild cramps... I'm totally freaking out right now... What just happened??!