How to tell if i have mercury poison? will i live?

You'll live: Your physician can order a blood mercury level if you have vague complaints, and can recognize the cerebellar and peripheral nerve findings of toxicity clinically. If you have amalgam fillings, there are charlatans who will literally try to "scare you sick" and think you need to spend many thousands of dollars to have them removed. If you have exposure in the workplace, it'll show on labs. Cheers.