Doc Instruction Is To Take Primolut 2 Days Before Menses

Doc instruction is to take Primolut 2 days before menses starts, 1 tablet twice a day. I started taking it ytd AM however in the afternoon, I started bleeding a bit. This mean my menses this month came 2 days earlier. I did not continue to take the medicine ytd evening. However my menses stopped bleeding since yesterday evening. This mean the medicine already take effect. So I took 2 tablets this morning again, but now i see that there is little bleeding again. Can you advise should i continue or stop taking the pills.