usually you can get better if you keep playing against players who are better, and keep practicing. Just keep playing against other people and get comfortable in game

I agree with RainMan and Grabtherebound. The more you play, the more comfortable you become. But while you play, continue to work on your skills by yourself. You can't have one without the other. You need the discipline to do both.

Play one one one, two on two, five on five, etc. All different ways you can learn the game and improve.

Good luck!

Keep playing against players that are good and you will get better.  Kepp up the hard work it will pay off

I think you're scared of failure which is common with all athletes. But you struggle through failures to reach success. Just go to the park , or join a rec team so you can get use to playing a defender. Or, a gym membership . Use your time to play better players and your game will elevate .