Ok, to start with, I would encourage you to breathe and put things in perspective. It sounds like you are really, really stressed out. Cavities and even tooth extractions aren’t necessarily the end of the world. Especially if you can get a white filling. Yes, it’s ideal to keep all your teeth, but plenty of people live to a ripe old age without. My grandmother died in her mid-nineties with plenty of mercury fillings in her mouth.
That said, I don’t even know how much evidence is behind Nagel’s protocol. I would not go into the poorhouse following it. If you can’t afford that stuff, why not just try to eat liver once a week and take vitamin D, which is pretty cheap. Whatever causes the least stress. If you have an otherwise decently healthy diet, you’ll probably be ok. I know people with 0 cavities in their life and I assure you they eat bread!
It sounds like more than anything, you need a stress reduction routine.