Re: I don't know what to do...

Telling us more about your symptoms probably would provide clues--mood, fatigue/energy, immune system, gut issues, changes in intellectual abilities, dizziness and weakness vs athleticism, food sensitivities , etc.

So may systems in the body are related, especially when you know hormones are involved.

For example, Functional Medicine tries to connect the dots. If your mainstream docs can't get to the bottom of it, a FM doc may be able to do so.

https://www.ifm.org/functional-medicine/

For example, WHY are you iron low? This may provide leads.
https://www.wellnessresources.com/news/stunning-discoveries-regarding-iron-obesity-candida-thyroid

If your IUD contains copper, learn about copper toxicity. I've seen a few reports of that over the years with IUD.

There is so much more that could be discussed. There is no reason to give up hope.