Hormonal coil (IUS) and lower back pain

I've had the mirena coil for four months, I'm still bleeding irregularly (period every 8 days) and lots of spotting. I've been dizzy for months, I'm feeling very low, I have water retention and a lot of lower back pain that feels like a pinched nerve so I'm battling to concentrate on work. I really want to have it removed but I'm terrified of going back to the alternative of extreme heavy periods that made me anemic.

The insertion process wasn’t pleasant and I found very painful however I will say it was very quick and the pain didn’t last. After leaving the doctors I felt fine apart from a little light headed but that was due to me stressing. The next day if I didn’t know if had it fitted I would be none the wiser as I felt normal and had no issues. Since then I have really liked not having to think about it, I had no periods at all but have started to get a day or so of spotting once a month at the 18 month mark and some light cramps. The only other negative to me is that it’s meant that I now always have to use lube for sex as it’s definitely affected dryness. The best overall contraception I have tried

Random cramps throughout the day, they suddenly stop and start again a few days later. Period almost completely gone, but random spotting through ovulation and calculated period days (on clue app). Very bad breast tenderness during ovulation and periods