Expenses and anxiety

Hi everyone, i have a hole on my 2 front teeth, it hasn’t been painful (yet) however it has started to get sensitive, I’ve been to the dentist and they (2 different practises) have said it is close to the nerve and needs to be filled soon or it will need a potential root canal, I’ve been to the hygienist and had my teeth cleaned, next step is the filing which I can’t afford yet and wont be able to for a while, even on the NHS, I understand I’ve been an idiot and because I’ve ignored this I can’t blame anyone but myself, i have so much fear and anxiety around the dentist, i have suspected autism, and extreme anxiety, i struggle to do basic tasks like talking on the phone or speaking up for myself when needed, i worry that what if i swallow my tongue, what if I’m allergic to the injection stuff they use to numb the tooth, what if i pass out because of the anxiety, its a hole that is quickly progressing so any advice on how i can get cheaper dental care and help with my anxiety around dentists (or if the nhs offers payment plans) would be much appreciated,

Thank you for your time.