You need to get the amalgams OUT. Yes, what you're experiencing is related to mercury absolutely. I would suggest that at this time, you might want to get yourself as healthy as you possibly can (which might be almost impossible) by cleaning up your diet by not eating sugar, yeast or gluten grains. This can begin to help your gut, lessen the candida in your body (candida comes with mercury, it causes it's own suffering also) and help your immune system a little more. Take things like vitamin C, some selenium, vitamin E, magnesium, zinc and milk thistle if you can. These should help a little. Don't take vitamin C near a dental appointment, as it erases the effects of the anesthetic. So stop taking vitamin C about two days before the appointment.

When you reach a point of having your amalgams out and replaced with composites. Then you need to get on a safe chelation/detox programme to begin helping your body eliminate the stored mercury. Andy Cutler's protocol is the safest I've heard so far. You might want to join the forum where people use his protocol. It is called frequent dose chelation and the other one is adult metal chelation.

HOpe this helps a little. Main thing now if you're not already, is to help get yourself a little stronger in the meantime with diet and supplements to prepare yourself. Sometimes diet is absolutely crucial to help cope easier with the mercury.

Best wishes and hang in there.