What's your take on metal dental fillings?

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Just wondering what everyone else's thoughts are on metal dental fillings? I know there's a lot of research out there both ways that's inconclusive on whether the mercury in them causes ill health, but I can't help but wonder. When I was young my dentist filled my entire mouth (I'm talking every single tooth and in between) with metal, telling my parent's it would prevent me from getting cavities. I have struggled with chronic fatigue and other symptoms that no matter what over the years I haven't been able to shake. My doctors have ran every test and never been able to figure out what it is. I'm wondering if this could be the root cause.
I'm also wondering if anyone has had them taken out and replaced, and what the procedure/costs were like?