You get used to it. I have bad luck with my teeth despite being careful with it and had about 6-7 fillings done within 3 years and just finished my root canal procedure today (one filling got infect =.=")

Maybe find another doctor. A good doctor will really take care of the patient and can make a huge difference. I'm terrified of dentists to the point of tears but my current one is amazing and I'm not afraid to visit him since he's good with his methods.