I worked for a "big 4" (Google) for many years, and now I lead the engineering team at a startup. I've interviewed many hundreds of people. And I've "been there" in anxiety about interviewing for something new.
Let me make you a deal: call me up and I'll interview you, no "puzzles". Except instead of this being about a job with me, I'll give you feedback from the interview and any advice I can. You can reach me at mikey@ (domain in my profile).
(Depression signs are another matter; others have given some good advice there.)
I've taken and given a fair number of engineering interviews myself (though not quite hundreds) and am willing to echo this offer. My email is in my profile. I'm happy to lend an ear on other issues if you want, I've been to some dark places myself and could offer some perspective.
Thanks! Can't edit my post, but didn't expect such a positive response, really cool to see others offering an ear as well.
OP's got a _lot_ going on here: fear of being stuck at a prestigious company; team/interpersonal struggles; the feeling of vulnerability from bombing an interview (which was also "the one" opportunity); possibly burnout; and the potentially very serious signs of depression. Thought I'd try to take a chance at demystifying some of the demons I know better, I'd probably learn a bit too.
Whether or not he or she reaches out, there are a lot of other great responses here, and I hope OP can at least feel less alone.
Excellent gesture, excellent thought, worth replicating like others have.
OP - I'm also happy to do a mock interview for free. Feel free to reach out (info in the profile), whenever you feel ready. [Disclaimer: I run a for-profit in the space, but we're all humans first]
Let me make you a deal: call me up and I'll interview you, no "puzzles". Except instead of this being about a job with me, I'll give you feedback from the interview and any advice I can. You can reach me at mikey@ (domain in my profile).
(Depression signs are another matter; others have given some good advice there.)