Never ending period 😩

I have a 4 month old daughter. 6 moths pp I had the IUD placed. I had some semi-light, dark brown colored bleeding for about two months straight after getting it placed. It stopped for a couple weeks, and I got my period about theee weeks ago I stopped bleeding red and now it's just constant dark brown. It's been dark brown for about two and a half weeks now. I'm with this guy, and I want to have sex with him, but I can't if I have this brown stuff coming out of me!! And I don't want to wait until it stops (though I might have to) because I don't know when it will stop. It could stop in a week or it could stop in a month. What should I do???