IMPLANTATION SPOTTING / YEAST INFECTION / HPT

I HAVE BEEN OFF B/C & HAVE HAD 2 "NORMAL CYCLES" - THE LAST ONE WAS 30 DAYS APART. I DEVELOPED YEAST INFECTION SYMPTOMS LAST WEEK & JUST STARTED TREATING THEM. I AM NOT PRONE TO YEAST INFECTIONS & WHEN I START FEELING THE FIRST SYMPTOMS THEY USUALLY GO AWAY ON THERE OWN. I HAVE NEVER TREATED A YEAST INFECTION BEFORE W/OVER THE COUNTER MEDS. MY LMP WAS MAY 26TH & I WAS DUE FOR MY PERIOD ON JUNE 24TH. I STARTED VERY LIGHTLY SPOTTING ON THE 22ND, FIRST A BROWNISH COLOR & THEN A PINKISH COLOR. I NORMALLY GET REALLY BAD BACKACHES ON DAY 28 & HAVE HAD NOTHING. I HAD SEX ON THE 9TH & 17TH, UNPROTECTED. I AM WORRIED THOUGH, BECAUSE I HAVE BEEN DRINKING ON THE WEEKENDS & TANNING, WHICH IS NOT MY NORMAL ROUTINE. I TOOK AN HPT TODAY (JUNE 26TH) & IT WAS NEGATIVE. I HAVE 3 BEAUTIFUL CHILDREN & HAVE HAD ONE MISCARRIAGE, WHICH WAS DEVASTATING, AND THAT STARTED W/SPOTTING. COULD THIS BE FROM A YEAST INFECTION, OR MAYBE IMPLANTATION SPOTTING, OR A VERY EARLY MISCARRIAGE STARTING??? THANK YOU FOR YOUR HELP.