It is very difficult to get less than 1mg of copper per day from diet. Iow it is very easy to get a lot more than that just from nuts, seeds and legumes
Anything is possible... you might have zinc toxicity.
Zinc can antagonize other minerals besides copper. 15 mg is not that high a dose so you have some serious underlying condition.
Any problems with your fingernails?
Panic attacks could be associated with overloaded liver.
Are you on a dogmatic diet like vegan or anything extreme?