Getting Out of a Rut
Welcome to depression. You are burned out and fighting for a dopamine hit, hence the overindulgence. From time to time you become motivated to change, which too becomes a source of dopamine, dreaming about doing it, but never following through, because you never have the energy, and motivation is just as fleeting as the high you get from porn, games and food is.The first thing you can do for yourself is changing your environment, or at least your routine, to as significant degree as you are able to, to avoid those frequently taken pathways in your brain that are wired to familiar signals. Non-familiar is your friend. Becoming a father should be able to help with that. We are highly affected by context, so fixing your room and your appearance will also help.The second thing you can do yourself is introspection. You have to start to face the music, no matter how painful. You can't run away from your problems Shinji. To be able to deal with them, you have to identify them. Know thyself. This is where a psychologist can be helpful.The catch is that both of these takes energy, support even, so don't fret if you keep failing, but don't give up either, escapism is not the answer. I have a  useful tactic for bridging the intention-action gap:1. Make it easy (effort) by increasing your ability to act or minimizing cost. Tiny steps, worth doing badly.2. Make it attractive (reward, incentive), increasing motivation by highlighting benefits.3. Make it timely.Time and effort discounts the value of reward. We are wired to obtain rewards as soon as possible, spending the least amount of energy. The solution is to think big in the long-term, but small in the short-term. The cumulative effect takes care of the rest.Besides this tactic of how to act, you need a strategy (what to do, what not to do, how to avoid bad cumulative effects, how to promote good ones) and a direction (how you perceive reality, flexibility, self-compassion helps here, as do a psychologist).Again, don't forget, motivation is temporary. Small changes and improvements every day are cumulative. It still takes energy, support even, which is where fitness, sports, talking to the people in your life, making new friends can help. You can't always do it on your own.