It's all in your mind, man
How are you intellectually ?
I mean; What do you choose to focus your intelligence on ?
(here's a new one: It takes intelligence to understand how a car works, and how to improve it's function... The illusion that intelligence is only in reading books and knowing facts, is just that... an illusion.)
If you've chosen not to chase higher education, then that is something you've chosen, it doesn't make you less of a man.
So, hand them a rap with a pretty bow on, about how you don't follow the stressful idea of trying to increase ones value through diplomas and education, and instead focus on the things that bring you happiness.... Something like that.
Get comfortable in your skin, and decide whether the situation you're in currently is one you would feel good about, and if not, change it.
No excuses to yourself, if there's something in you that chooses to believe that higher education means something if it doesn't grant you the access to the kinds of job or position in life that you want, then rethink it once more, and then make the decision.
Don't hesitate to change your life into what you want it to be.
Secret excuses unto yourself is unacceptable.
You're you, and you're in the position that you want to be, and if people don't like that then fuck 'em.. They're not you...
As Hendrix said "I'm the one who's gonna die when it's time for me to die. So let me live my life the way I want to."

Inner game man,
Get your confidence wrapped.
Cheers.