It sounds like you have some extremely strong Ugh Fields. It works like this:
A long, long time ago, you had an essay due on Monday and it was Friday. You had the thought, "Man, I gotta get that essay done", and it caused you a small amount of discomfort when you had the thought. That discomfort counted as negative feedback, as a punishment, to your brain, and so the neural circuitry which led to having the thought got a little weaker, and the next time you started to have the thought, your brain remembered the discomfort and flinched away from thinking about the essay instead.
As this condition reinforced itself, you thought less and less about the paper, and then eventually the deadline came and you didn't have it done. After it was already a day late, thinking about it really caused you discomfort, and the flinch got even stronger; without knowing it, you started psychologically conditioning yourself to avoid thinking about it.
This effect has probably been building in you for years. Luckily, there are some immediately useful things you can do to fight back.
Do you like a certain kind of candy? Do you enjoy tobacco snuff? You can use positive conditioning on your brain the same way you did before, except in the opposite direction. Put a bag of candy on your desk, or in your backpack. Every time you think about an assignment you need to do, or how you have some job applications to fill out, eat a piece of candy. As long as you get as much pleasure out of the candy as you get pain out of the thought of having to do work, the neural circuitry leading to the thought of doing work will get stronger, as your brain begins to think it is being rewarded for having the thought.
It doesn't take long at all before the nausea of actually doing work is entirely gone, and you're back to being just "lazy". But at this point, the thought of doing work will be much less painful, and the candy (or whatever) reward will be much stronger.
All you have to do is trick your brain into thinking it will get candy every time it thinks about doing work. Even if you know that it's just you rewarding yourself, it still works. Yeah, it's practically cheating, but your goal should be to do what works. Just trying really, really hard isn't just painful; it also doesn't work. Cheat instead.
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