Why do i panic about getting shots?

Needle phobia: Tends to run in families and many have inherited what's called a vasovagal reflex in response to fear. When they see a needle or get a shot, this triggers the vagus nerve, which widens blood vessels, slows heart rate, and drops blood pressure. But a fear of needles is also brought on by a negative experience in a doctor or dentist's office usually before the age of 10.

Trypanophobia: Great response by Dr. Reynolds. I had a brother who had trauma related to shots & was terrified of them. The good news is that this is treatable. Please consider cognitive behavioral therapy.