Nervous and slightly frustrated! Help?!

I was diagnosed with PCOS a few months ago and I am a TTC newbie after a miscarriage last November. This is my third month on 1,500mg per day of Metformin. I am 16 dpo (are you supposed to count from first day of ovulation?) my period is supposed to start in 3 days. My breasts have been incredibly tender, however, I had a faint pink discharge when I wiped after peeing earlier. Should I take a PT or just wait to see if it's my period?