People who go to the elite institutions and get jobs at the elite companies didn't all get there because they're better than other people. Some did, sure, but many others got where they are because they had a head start. Wealth and connections still have a huge impact on outcomes.
The second thing to do is to understand that how happy you are with your life is basically up to you. You can do pretty awesome things, and be very happy with what you do, even if you don't work to deliver adverts faster or hoover up more personal data while making a few billionaires a little bit richer.
Not by some stupid elite standard, but by your own standard.
Stop comparing yourself to others. Be yourself, everyone else is taken.
Who cares about stupid elite schools and companies? Go live.