Why are my teeth decaying so quickly?

Less then two months ago, all my teeth looked perfectly fine, accept for one in the very back. A wisdom tooth was black with decay. But the rest of them were fine. Now, almost every tooth in my mouth is rampant with decay. Why would this happen in such a short period of time? It makes no since. I'm worried i'm going to end up loosing all my teeth. I can't afford a dentist. My insurance doesn't cover dental. Not sure what to do. :/  

?2020-12-15T17:41:46Z

Could be wearing masks. You’re breathing in a lot more carbon dioxide which I believe is more basic than oxygen. So you’re altering the pH of your mouth. 

Just because it looks fine doesn’t mean it’s fine. You need a dentist and an x-ray to see what’s really going on.