1st thing to remember
* it's a game
After there's cheating. It's most of the time unfair competition.
No matter what you do, how much u study there are clubs of cheaters poised to prove something they can't admit to themselves. We all know what it is.
I had easter break from school for 2 weeks. I spent the first week training 24/7. I was expecting to play my best chess and wanted to gain some rating to approach 2200 FIDE. The second week I played in the French under 18 championship. And I played TERRIBLY. I lost to an 1800 first. I didn't mind much because it happens I guess, but then the second defeat against another 1800 devastated me. I then lost game after game after game. Losing to more 1800's even a 1600! Last round I lost to a 1500. I played so badly. I missed obvious moves by my opponents, took so long to see basic tactics and threw easily winning positions up material.
I'm going to lose 200 rating. I don't think I'll play much because of school in the next 2 months. How do I recover from the trauma of that tournament? I can't think clearly doing anything now since the memories of missed wins and blunders keep coming back. And I started doubting my level of chess. Did I lose my level? Maybe I was overrated and just got lucky in the past? How do I recover psychologically?
Tygxc said it best. Power through and comb through your losses. I haven't had a catastrophe like that in a while, but always consider your psychological state in your analysis. Were you nervous? Why were you nervous? Did you look at his rating too much? were you frustrated at not being able to win quickly enough? etc.
I usually go into tournaments with low expectations. I always surpass them!