Moms with experience or a dentist please help me!!!..?

Please don't judge me I am the best mom my son could ever have and I spoil him to death. - okay, my son is 3 years old and he has cavaties on all his four front teeth. The first time I took him to a dentist was last year february when he was two and he had a lot more cavities the dentist told me the ones in the back had to be drilled first cause they where more dangerous. Okay I went to 4 different appts fron feb-april because each appt they did like 2 cavities. When it came time for my last appt to get his four front teeth removed they took away my medicaid. I went like a year trying to get his medicaid back(told me I was making too much money. Pff! $10 an hour and I'm a single mom) anyways now my son's front teeth are completely gone they're black! When I tried to go to his old dentist they didn't accept his new insurance plan. I took him to a new dentist and she told me "mom he has a lot of cavities" and I looked at her with a face like I know stupid what are u planning on doing. She just told me if I WANT talk to front desk and schedule another appt. Wth?? And she left she wasn't concern like his old dentist was. Ok my question is I'm scared that till august that the cavities might hit a nerve and something happens to my baby???!!! :( I'm sorry I've been a crappy mom I did let him sleep with the bottle till 2