how do you carry yourself with confidence and self assurance?

Question

i'm a male in my early 40s and ive never had great confidence or self esteem, because i was shy as a youth, came from a respectful loving family and i encountered rough bullies who constantly undermined my confidence, and it had a lasting effect on me.

now as a man, i live with a personality disorder, terrible nerves and ptsd....and when i have to go out in public i'm very nervous, easily startled and panicked, and self conscious and find it hard to carry myself with confidence.

how do i achieve it?

Update:

i'm also bald, have a moustache.

Update 2:

i meant to put 'self assuredness'.