Do you have other OCD symptoms? It does sound like mild OCD (chronic is where the person has to do rituals). Within 2 years of getting amalgam as a child, I had chronic OCD.

That said, you may have something of post-traumatic-stress syndrome aswell. One thing that often isn't discussed is the psychological trauma of what we're all going through, with having to cope with having been poisoned by dentists/medical professionals we trusted and all the health consequences, the lost years to mercury, and family or friends not believing us or wanting to talk about it. In that way, it's a natural reaction to develop a fixation/obsession with mercury because of the trauma.

Mercury can cause OCD and anxiety problems.

I relate to what you say as it's happened to me, and not just on mercury. I worry about germs and other things that might contamination me or my house, and it's not easy.