Yep, Copper overload or hypercupremia as they call it can cause feelings of depression. Although it is more commonly associated with paranoia and an overabundance of norepinephrine which causes feelings of aggression or hostility etc.
You might want to try supplemental zinc as that binds to excess copper in your system and takes it out. It is also a good tissue antoxidant and helps heal a damaged gut.

My advice is to go gluten free. No promises about your symptoms clearing up but I definitely think you will experience reduction in some of your symptoms. You will be amazed at how many ceilacs also suspect mercury toxicity. there is Definitely a link between the two.
Just hope the world will wake up soon enough.