Family history of mental illness doesn't mean that your amalgams are not responsible for this.

if there is a history of mental illness in your family it could mean that your brain is more vulnerable to toxins than in other people.
Your family probably does not tolerate heavy metals very well.
The medical establishment has told us the lie that our genes are responsible for our illness. Our genes never cause disease, they can tell us only if we are more vulnerable to certain things than other people. Some people don't tolerate our high sugar diet and get diabetes, others don't tolerate heavy metals and get depressed.

You are doing the right thing. Chelation and amalgam removal is the best thing you can do for your body and your mind.