birth control and periods

So I have been on birth control(pill) for a little less than a month now and I got on it because of heavy periods. It's suppose to make my periods not be so heavy and reduce cramping. My period was supposed to start this month on the 4th and end on the 9th. On the 5th is when this started to happen: When I use the rr and wipe the paper is red but not every single time, I put on a pad bc I thought I started but it wasn't stained at all. I have had cramps but they're not too bad.. So idk if I am on my period or not.. but is this normal? I mean I haven't been on the pill for long.. Does it start working fast? I know the doctor said my period wasn't going to be as heavy but I'm just not sure if this is what is supposed to happen.