Hey I once procrastinated an application for a nation-wide state sponsored contest for new writers. You had to provide 40 pages of material + an additional piece of art of any type that you'd made in response to a series of prompts of theirs. I had a year. I did it in a day... They told me it was some of the best stuff they'd read in years. I once wrote 70 pages of an urban planning project in a single night and got an A.

This isn't to humblebrag, this is to calm you down: Don't discount your stream of consciousness.

You've been thinking about the project for a lot longer than 15 minutes, you've been moving the pieces around in your head. Writing it all with no time for corrections isn't necessarily as bad as you fear: it means you also had no blocks, no time to stop, no time to diminish raw unfiltered power pouring from your brain onto the paper.

You wrung your mind and heart out in the time you had, because you couldn't do anything else. You didn't have time to hold back. That might not be a bad thing.

You're going to be all right. Whatever you gave them is far from the worst they've received and it is at least interesting. It will be fine.