21 weeks pregnant, panic disorder, and needing 2 root canals...

I found out before I was pregnant that I needed to have 2 roots canals done but after finding out I was pregnant decided to put it off until my doctor said it was ok, So now I have to go have 2 root canals, I’m only in a rush because I’m afraid I will develop an infection and die and/or pass it along to my baby, Plus it hurts pretty bad.. I have an extreme fear of dying in the dentist chair as soon as they remove the infected tooth, Also now when I recieve novicane shots and my mouth and throat become numb I start to panic and feel as though I can’t breathe, What can I do or ask for to help my situation? I really hate the feeling of not being able to breathe