Hi, firstly I would ask for a scan to check that the coil is in the right position.
My daily bleeding (mainly brownish sludgy stuff, not heavy) went on for around 6 months, then became gradually more intermittent. After around 12 months I finally stopped bleeding and have had none since (I’ve had the coil for 2 years).
This seems like a very long time to put up with this but after I was reassured everything was fine after a scan I was determined to persevere as utrogestan brought me out in a rash and I needed to be on 4 pumps of oestrogel.
I hope it doesn’t go on as long for you but now mine has settled I feel it was worth the effort as I now don’t think about it at all 🙂