Help bleeding after period

Hey guys so I’m on the combo pill and I take it every single evening around 9. There are a few times where I take it later around 12 but it’s fine. I just got off my period around a week ago and my boyfriend and I have had sex twice since then. He always pulls out and now I’m having light to dark brown milky discharge. Is this breakthrough bleeding or just old blood making it’s way out? It’s not enough to wear a pad- maybe a panty liner. I know implantation bleeding is super rare when on the pill and Im literally on the pill so I’m not too worried about being pregnant. Just wondering what it is if someone could please help a sister out