Hello i was a week late for my period, but then had a brown/red discharge which i umed was my period?

i have recently been prescribed yasmin bc and thinking this was my period i started taking the pill. the "bleed" only lasted 3 days and was more spotting than a period i have done pregnancy tests all negative, could i still be pregnant and if not will i be covered by the pill from now on if this wasnt my period???