The way you treat yourself needs to change. You constantly discipline yourself, and not in a useful way like the ideal Stoic would. You take it too far, like Marcus did at times. You’re too much of a realist and your avoidance of pleasure is counterproductive.
A part of you thrives on being tough on yourself. You get off on setting impossibly high standards for yourself and trying to live up to them. This is intellectual and emotional masochism. And while in some ways you can’t argue with results, in other ways you’re just killing yourself slowly.
You are a skilled musician and your’re competant mathematically, but you didn’t get there by enjoying it. You got there by forcing yourself.
It’s time to start enjoying life more. It’s time to stop forcing yourself to do what you think is right because of some bullshit abstract poptential payoff after it’s all over. There never really is an end to it anyway.
Instead, what I propose is this: Let yourself slow down. Let yourself drift a little. Feel yourself drawn to certain things not because they seem important or beneficial or smart or noble, but because they awaken your soul. Because you can’t stop thinking about them. Because you’re losing sleep with obsession.
This is not passion. The answer will not be big and loud and obvious. You won’t discover upon waking one day that you were born to throw pottery or measure test tubes. It will be subtle. It will present itself as a long-lost habit, a way of thinking, a style of working, a certain topic or aesthetic. It will be the things that excite you, that distract you, that make you stare at the wall and accidentally ignore people when they say your name. But it will be the seed from which mastery can grow. Do not be in such a hurry to figure it out and to find success. Look for the omens.
You do not need to worry about not working hard enough. In your case, ambition will take care of itself. It is a deeply-rooted habit, and it will keep rising to the surface like a buoy. No, what you need is a counterweight to keep it from taking over and causing you unnecessary pain.
Above all, remember Grand Strategy and refer to it often. Fly over your life at a high altitude at all times, constantly surveying the landscape. You are not bogged down in infantry battles. These will give you tunnel vision and make you emotional. Instead, your position lets you see the whole battlefield and guides your decisions and thoughts.
Be calm, and assess the terrain.