Brown Bleeding on the Combined Pill

Hey guys, just wondering if anyone can give me any advice/experience for my problem,

I started the combined pill, Microgynon 30, about a week and a half ago on the first day of my period. And since I started I’ve had dark brown blood like old blood at the end of your period, with some light red blood occasionally coming through too. I thought at first it was my period taking a while to finish but I’m sure it’s to do with the pill now. I’ve read that bleeding between periods is normal at the beginning of the pill, but was wondering how long this normally lasts for, as me and my boyfriend have an active sex life and I’m very embarrassed about it every time we get intimate.

Does this normally last long? It’s everyday and it’s quite heavy like the last days of your period.

Also I’ve read that it can affect the effectiveness of the pill, does this mean it’s not working properly because of the bleeding, because I don’t see the point if it’s not effective contraception.

Thanks for any help you can give me!