No AF, OPK positive sept 21, BFN!! HELP PLEASE..

My last period was aug 15-21, to this day still no AF, i have been having cramps sore breasts and occasional nausea. I had 2 days of light spotting on sept 14&15, then again on sept 18,19,20 but only bleeding light pink when i wipe. I ovulated according to my opk on sept 21, still no period and multiple BFN hpt. Not sure what to think, have a dr appt tomorrow but i am still curious.. Any Help??