Does Slight Brownish Vaginal Discharge Indicate Pregnancy Or Ovulation?

I am 25 years old. I am taking metformin for last 3 months.IMy periods are not regular. iIam suffering from pcos. i had an abortion 8 months ago. that pregnancy was spontaneous. my lat period was on januvary 20.today i had a slight brownish discharge. willthis be a sign of pregnancy or ovulation?