Always amazed that everyone sticks to the old defunct theories from over 100 years ago, that narcs suffer 'low self esteem, that they are insecure & hurting' blah, blah, blah.

The pathological narcs I know (including my mother) do NOT suffer those things.

IMO most narcissists are like psychopaths, born not made. A good loving home environment will mitigate the PD, a bad home will exacerbate it.

Years ago parents were thought to cause Autism, they were assumed to have been at fault, by being cold, uncaring 'refrigerator' parents.
Now we realize this is not the case.
Psychopaths were thought to be made by unfit parents, now it is thought they they too are 'born that way' Brains scans have revealed significant differences in their brains.
How I discovered I have the brain of a psychopath | James Fallon | Comment is free | The Guardian
Narcissism and psychopathy are closely aligned, all psychopaths are narcissists. The link is the total lack of empathy the inability to feel for others.
Likely a fault with the Amygdala.

I do not think you are a narcissist. You are someone suffering from the effects of living with narcissists.

I never feel like anything I do is good enough, etc. - the usual stuff when you're a child of a narcissistic parent.

Yup, thats what they do to you. A crippling lack of self esteem, lack of confidence, OCD and social anxiety has made my life very difficult.
I always wanted loads of friends, but was too shy to make any.

You sound like a decent person, who has insight into themselves. You are not narcissistic. You may have traits of narcissism learnt behavior but with help, maybe therapy, that can change.
Build your self esteem, you are good enough, you are always good enough.