CalebCalebI'm bad and I always will be
There's your problem, your attitude is keeping you down. You can show marked improvement and dig yourself outta this hole by reviewing your own demos, comparing them to top players, taking notes on what you do right and what you do wrong, etc.
There also lies the fact that you're overthinking everything, and letting anxiety dominate your mindset. TF2 is also about mentality, so I'd recommend doing some meditation and other mental exercises before hopping into a game.