>but my brain won't let me
Who's in control here, you or your brain? Trick question. You are your brain. The concept of you is an abstraction created by the brain. However there is give and take in that relationship.
You, the concept of yourself (from this point out I'm calling this your ego), have physically changed your brain, which in turn changes the ego, and so on in an infinite feedback loop until one of you dies.
That's the situation you're looking at now. So how do we fix this?
You abandon yourself. You let go of your ego. You're telling yourself "I have no motivation" "I need to be on 4chinz" and so on. You don't. You're caught in the loop.
So how do you stop yourself from being you? You catch yourself in the act. The moment you sit down to play vidya, you stop, take a second, and say to yourself "I need to be doing x". When you're feeling depressed and lethargic, you need to catch yourself, and put that depression somewhere else. Personally, I like to write. I'll get out all my bullshit onto a few pages, and on that paper is where it stays.
This practice of catching yourself is known as cognitive-behavioral therapy in professional mental health circles. You are developing a cognizant understanding of your thoughts, and choosing a behavior that either diverts the thoughts or works to settle them somehow.
It's hard to do, I'm not going to lie. And you'll get to a certain point where you'll go "holy shit, am I really thinking like that this fucking much?" and that may be discouraging. And it's going to be a slow process since you've built up these thoughts and behaviors for several years. But to fix yourself, you have to break yourself down, and that starts with your thoughts and the ego.
Dismantle the ego, it's serving you no purpose but slowing you down. You are not your past, you are what you are doing in the present, and right now, you're committing to killing that ego, and building up a new edifice.
