I have a medical question. Need advice.

My last period was the 9th-14th, and it was super heavy, so Meilke(my ob) had me start birth control. Taking two for 4 days, and 1 after until the pack is gone. I had spotting 4 days after my period, and have been bleeding since then. Some days it’s spotting, others it’s almost like period bleeding, and sometimes it’s brown bleeding. I heard it’s common to have two periods in the first month of taking birth control but I didn’t know if this is normal? What’s your opinion on it? I’m on my last row of birth control tomorrow. Sorry, it’s that’s tmi. I called my ob office and no nurses work today.