Many dentists are hesitant to extract your back teeth (molars) --and I'm assuming this is where the Amalgam filling is located?-- because if too many go missing back there, you may have trouble with chewing/breaking down food properly.
But a lot of people do have many teeth missing & they get along just fine. You can always (later on in life) consider partials/bridges/ and even an implant later on down the road. There are also avenues you can pursue that will help you get dental work for free. Call around to dental offices, health department, schools, etc and see what you can dig up. I own a private dental lab that makes custom fit night guards for people that grind their teeth at night. We make the same exact night guard and charge way less than the dentist so like I said, there are alternatives. I'm sorry to say we don't make teeth but if you are in need of a night guard to protect your existing teeth you may want to consider us. Here's a link if you're interested http://sentinelmouthguards.com/about-night-guards/