Hi Emerzer,
First, I want to tell you that one result won't dictate the outcome of the rest of your life. I know that right now it sucks to feel that you weren't able to live up to your full potential, especially compared to others. But it's really important to know that comparing yourself to your friends (who maybe even have their own doubts about their own tests that they're not vocalising) takes away from the fact that you've done so well in your own right. Even showing up to a scholarship test. That in itself shows that you're a dedicated student!
I, for one, don't think you're stupid. I actually think you're very sensible for being able to point out where and how you went wrong, and are able to reflect on what you need to do to get better.
This scholarship test might feel like the only chance you have to prove yourself but it really isn't. There are countless opportunities out there that you can apply for and ace, especially in the next few years. Assuming you're at the start of year 10– you're still so fresh into VCE and you have so many opportunities for growth and change (a.k.a you'll be studying for a lottt longer than this, and will improve!) Humans are forever-changing, and it's not fair on your mental health to expect the 100% best all the time when that's not realistic.
My advice to you right now– go play a game, watch a movie, something fun to get your mind off things. If you're really feeling down, reaching out to someone like a close friend or sibling can help you get these thoughts off your chest and help you feel better.
If you need any help or want any advice pls don't hesitate to message me or any nice member on here (: