If such is the case than Amalgam probably is the extra load to your body, not initial cause. However, I wouldn't write off toxicity yet, because there could be a possibility of other substance which your body react to.
Regarding the hair mineral analysis, I would say yes and no. Because there are people whose hair mineral analysis just show false negative. If hair mineral analysis doesn't do the work, maybe choosing urine test would be another alternative.If you can, avoid test that can be backfire (like dmps challenge). F or the first step I think doing hair element test is good. It's not only show whether you have any toxic element in your body (though you have to be aware of false negative possibility), it also show which are the essential elements your body lack of (or maybe out of balance). Finding a good lab is also important.
Also, I hope this won't burden your mind (I mean if it's burdening you too much or you can't remember, simply ignore this suggestion). But I find it helpful if you can remember what you did or what happened to you before your health start deteriotating. First thing come to mind is not always the right indication of the start of the problem, but it will give some clue. I realize that our body is not suddenly run into trouble, though symptoms may occur after sometime. For example: If you start to feel bad after you start a new lifestyle, even though after some time (like go on diet or change to vegetarian or simply avoid or eat too much certain type of food) you need to be aware of it. This is just a simple example. There could be lots of possibility. You can read previous posts here on the forum to see various causes.
Meanwhile, take a rest and eat well. Any supplement or regimen that you want to take, always remember to do it slowly one step at a time at a very low dosage. Different people react to different things. What works for others may be a trouble for you and vice versa.