It is good to be a little scared of failure. But you don't need to be terrified. If you are still young, you will have time to recover. It may have its bad moments (https://news.ycombinator.com/item?id=13445141). If failure looks imminent, make a plan B. But you don't need to live in fear.
Instead, look at what other lessons you can take from meeting the box-lifting chemist. Here is a guy with an advanced degree in chemistry who is working for peanuts. This could be an opportunity for you and him. When I was bankrupt, a complete chance encounter led to the job that pulled me out of that situation. I was having no luck getting a technical job. But while I was getting a haircut for another failed job interview, I told the hairstylist how difficult it was to find a job as a physicist. And she said, "Oh, I know a guy who is looking for physicists". She gave my number to a physicist who ran a small company. He hired me and it was a mutually rewarding relationship. He also hired other down-on-their-luck physicists and programmers. One of the current directors of the company was notably hired when the company founder met him as his waiter in a Chinese restaurant. By keeping his eyes open, this founder got great talent at a good price and now his company pulls in over $50M/yr revenue.
If things go bad, maybe you'll meet someone who pulls you back up while working at Trader Joes. If things go well, maybe you will be the person who pulls someone up.