Almost 30 and my teeth are falling out

[Charmed]

I haven't been diagnosed with Tricho Dento Osseous Syndrome. But many in my family has, and I know it's genetic and it would explain a lot of what I'm going through right now. I had many surgeries when I was young to do with my teeth, and braces for about 4 years. My teeth were fine until about 5 years ago. I had to have 2 root canals and after that, the teeth around those have cavities and others are know starting to get them. I have a small mouth, only 10 teeth can fit on my upper arch and 12 on my lower. I don't know if that means anything. I'm looking for advice. What do I do? How can I fix this when the price of dental implants is astronomical.