I used to feel the same way, until I worked through the fear to understand where it comes from;

It's born out of the traumatic memories that we carry afterwards.

You can confront those memories by writing them down and more importantly, making a note of the dissonance that triggered the narcissists scary behaviour.

The more you do this, the more you'll realise that the fear kept you safe from a very disturbed individual that you shouldn't have had to deal with. But now that they're gone, you can release that fear and start living your best life.