This is an excellent response. I'd like to add my support and voice similar sentiments for OP: I'm doing ok myself, and you've accomplished far more than I have. I know from personal experience that I'm my own worst critic. You may feel stupid, unskilled, or whatever, but when you begin interacting with people again, you'll find that you DO have plenty to offer.
A perceived failure is discouraging - but you've been gaining experience and growing along the way. This hasn't been a total loss.
I'm thirding this here, I'm about the same age, worked in a bunch of different things and technologies, helped startups create their product from ground zero, been to startup events and talks with investors and now I've accomplished my dream of being able to live abroad, out of my home country.
And even then I've not come close to the first hand experience you have now, 7 years driving two companies.
So don't be too harsh on yourself, you're doing very well, way above most of people even in your country.
A perceived failure is discouraging - but you've been gaining experience and growing along the way. This hasn't been a total loss.