It may be because you have failed at something you cared deeply about in the past. The reason that the feeling of failure is still current may be because it became a learned response-when something you care about is brought to your attention it may be an automatic response to believe you will fail at it.
You tend to feel like you will fail at everything you care about for that reason. You care about it. Often times when you find something or someone you care about you can be afraid that you will mess that up for yourself, and in reality you won't mess it up, but our thoughts can tell us differently. You just have to have faith in yourself and in who you are. And try substituting the thoughts of "oh I'm going to run everything" to "I won't ruin this. I am capable of anything" it is hard to switch to positive thinking but ALL of you are strong and amazing and you can do anything you put your mind too. Just take it one day at a time. I believe in you. 💕
Maybe you don't see what you've already achieved. We tend to only see the things we mess up, which all of us do, it makes us learn from our mistakes and that's a good thing, but oftentimes we just let what we mastered fall behind and concentrate on what we didn't.
The key is to try again. There are times you will fail, sometimes more and sometimes less, and in times where you fail more, you also learn more. It is important to get up again and try again. It'll pass. There'll be more opportunities. And you will be stronger every single time you decide to get up and try again.
The feeling that you think you'll fail is fear that you think your not working hard enough but you in all reality might be. You might even be an over achiever. Concerning yourself with doing well is good ambition and motivation to stay ahead and actually be successful