I completely understand that feeling, the main thing to remember is that it is not about how good you are. You could literally be the absolute best version of yourself and not get it purely because it isn't about you, it's about who you are up against. You can't control who the other applicants are so focus on being the best version of yourself.
Try not to worry about things that are outside of your control. You control yourself, so be the best self that you can. Much easier said than done of course. We cant help but evaluate every little thing that we said, but not getting through doesn't mean that you aren't good enough, if that was the case then they wouldn't have wanted to meet you in the first place. It all builds resilience and just know that you are not alone in your thoughts, who knows what GR are actually looking for! Be your best self and you'll end up where you are meant to be, when you are meant to be there.