anyone!!!!

Ok I have been posting for answers so here I go again. According to flow I got my period one day before and I get 5-6 days of which this time it only lasted 3 1/2 days I stoped for one hole day then the next day I woke up with clear some blood lining that same night I had sex with my BF and after I cleaned I notice lots of brown blood with cum because he came in me. Today I woke up it's gone, before the short period I got 3 pregnancy test done all negative so now I'm lost and concerned... was it implantation bleeding or should I consider it as a period?!?!