Thinking is an action, so you most definitely have control over it. But it's like youtube or facebook. They have us addicted to "wanting to check it" and we can't stop, not because we physically cannot stop, but because somewhere we're defeated and underplay it's harm even for a moment, just for that quick fix. But drawn out, it's clearly doing harm, and the behavior pattern is clearly that of addiction.
Self loathing is just another one of those problems. Someone depressed is also that way. Like a cigarette that they cannot ignore, of all the things they could be doing, they choose this -- the one thing that is expensive and that can kill you and that will even get you dirty looks nowadays.
> I am outwardly extremely confident
Why did you put "outwardly"? Because you're not confident. So you are being honest with yourself, in that you're not writing lies. Except, why would "outwardly" matter? You're trying to make excuses as to why you shouldn't be feeling the way you feel. But that's the problem. Emotions defy logic, because they precede them. And an excuse is something that deflects blame but otherwise does nothing. It's a reason for inaction.
> overthinking everything
This is not related. It's your self-loathing that's got you down. Maybe you even have mild depression. Either way, that's the problem, and not anything else.
The simplest answer to your problem is love. You need to learn to love yourself. Culturally Eastern culture can be especially undermining of an individuals healthy mental image of themselves. The burdens of society and of parental expectations weighs heavy, and the environment is that of anxiety and judgementalism, and not that of love and forgiveness. But this pattern exists in the West also. I'm guessing you had strict parents?
As gh1 here has mentioned, having a routine or creating ways of taking your mind off yourself is one way to deal with self-loathing. Being immersed in a passion project can do it also, like a startup. If you're too busy, you have no time for hating, even yourself. It's also what people do after bad breakups.
But you won't have time for love either, and maybe that's what you need. Some don't waste any time after breakups, and choose to quickly move on.
I used to self-loath. But now I couldn't be happier with myself. And it really boils down to the realization that there is absolutely nothing wrong with me. All my imperfections are common. I am just like everyone else. My problems are boring. And it's like you said. I can get what I want. Then what's the problem? The only thing that got in my way, and that is getting in your way, is that self image. It's how you think of yourself that alters what you do with yourself. That's the only thing getting in your way. And THAT TOO is an incredibly common and boring problem! It might be personal and in your face, but objectively speaking, tons of people have similar issues and you are not flawed or hate-worthy in any unique or special way. You just have low self esteem.
It also helped to understand why I was that way. Turns out, there were self loathing people around me. Japanese society didn't help either. But seeing those influences as what they were helped protect myself. Thinking is done with cues. Much like writing prompts, there are things that get us going (like this post on HN does for me). So understanding and counteracting those loathing cues is also what it's about. What makes you hate yourself?
But overthinking is not going to help. Any thinking is not going to help. It's a symptom of the problem. Like wanting that cigarette or wanting to gamble or wanting to drink. You're wanting to think so you can loath.
The cure is with maintaining your emotional health and making that a priority. You may need a change in environment, a change in acquaintances, and even a change in diet. But what you need to do is stop hating yourself, and start treating yourself. What do you enjoy? I love cold brew coffee and mindlessly shooting hoops. I love playing with my kid. I love surprising my wife by cleaning the dishes before she wakes up in the morning. Treating yourself is an act, and it's the act of loving yourself. It takes knowing someone to know how to make them feel better. And for that, you should introspect and analyze. But all you really have to do is remember. You need to remember those times and those feeling you'd rather be feeling now, and figure out how to get back there. From then on, it's all action.
In parting, here is an exert from the movie The Beautiful Mind, just to illustrate my point about logic is not in anyway unique:
Nash: [Making an acceptance speech in front of the Nobel prize audience during the ceremony] I've always believed in numbers, in equations, in logic and reason.But after a lifetime of such pursuits: I ask What truly is logic? Who decides reason? My quest has taken me to the physical, the metaphysical, the delusional, and back. I have made the most important discovery of my career - the most important discovery of my life. It is only in the mysterious equations of love that any logic or reasons can be found. I am only here tonight because of you
Nash: [looking at and speaking to Alicia]
Nash: You are the only reason I am. You are all my reasons. Thank you.