What Causes Brown Discharge In Periods?

Hi, mayI had my mirena removed on october 8th had no bleeding or anything till 3 wks after i bleed heavy for 1 day and then light for 3 more days and that was it me n my bf have been having unprotected sex since removal n he's been pulling out i recently got on the pill last tuesday havent started taking it n my bf has stopped pulling out and the other day i went to the bathroom and had this kind of thick yellowish/green discharge w/a brown tinge in it this only happend once but it was a lot kinda looked like jelly and im freaking out wondering what it could mean? I answer your health queries right now ? Please type your query here...I had my mirena removed on october 8th had no bleeding or anything till 3 wks after i bleed heavy for 1 day and then light for 3 more days and that was it me n my bf have been having unprotected sex since removal n he's been pulling out i recently got on the pill last tuesday havent started taking it n my bf has stopped pulling out and the other day i went to the bathroom and had this kind of thick yellowish/green discharge w/a brown tinge in it this only happend once but it was a lot kinda looked like jelly and im freaking out wondering what it could mean?