Period and birth control

So I’m pretty new at being on the pill. If I get any kind of blood at all during my sugar pill week, does that definitely mean it’s my period and I’m not pregnant. I took a test this morning and it was negative and now I’m starting to have just a little bit of pink tinged discharge and that’s how it always starts before I get my period. So is this my period and I’m not pregnant. I’m on day two of my placebo pills