Possible miscarriage or overthinking?

Ok this might not be the right group but I wasnt sure where to turn to. So I'm on the hormonal iud since June 19th 2019. Since the beginning I have had problems with it but the doctor just tells me it's fine wait till it's been 6 months yadda yadda. So I went to the doctors November 8th because I was having pregnancy symptoms for that past two weeks but the tests were negative. A few days ago I was having cramping and I started getting a brownish/dark red bleeding. It got heavy yesterday to where I should of had a pad but used a pantiliner instead. I changed it twice due to the heavy bleeding. I was gonna switch to something heavier but when I wiped I had a big clump of white tissue. I've never experienced this and I know im young at 23 but I've had my period since 14 and nothing like this has happened. Since the white clump of tissue came out the bleeding has stopped. Did I possibly miscarry and what am I supposed to do now if I might have now that it's done. Do I get the iud removed in case my body is somehow rejecting it and this happens again? My boyfriend and I have quite a bit of sex and he doesnt wear protection or pull out. I'm just concerned.....🥺