I know exactly what you mean about computer games, I used to get addicted to them fairly easily and be able to play for 12-14 hours at a time. I've also been down that particular hole of "everything I do is pointless, I'm pointless, I'm trapped into remaining alive by the people around me".
As to what to choose to care about, I haven't got anything to suggest that I know will work. My instinct is to suggest that you start caring about societally-approved things like exercise or taking care of your mother because you're more likely to get external positive feedback that'll help get you through the uncomfortable parts and give you a sense of accomplishment. Or if you have a camera, start a 365 project. If you don't, start some other kind of creative project like writing or programming or whatever it is that you think you might find interesting. But.. I don't know if any of those suggestions are likely to help. You've been at this computer game thing for long enough that almost any other activity is going to look understimulating and difficult/uncomfortable in comparison. In my own situation I was helped along partly by a belief that I deserve to suffer, which meant that feeling uncomfortable often wasn't a sufficient reason not to do something. I assume you don't have that belief, which means you'll need to find some other reason to keep going rather than thinking "oh well, failed again, time to distract myself with some more games".
Ok, let's face facts. The Internet has fried my brain. I'm a terrible hedonist and procrastinator. I have a very important test in May -- I am not exaggerating when I say that the outcome of the test matters to the future direction of my life. There are situations where failure is just a temporary setback, and there are situations where failure would be a real problem, and this is the latter. No fooling.
My Problems
1. I don't work enough. My primary distraction is the Internet, though occasionally novels happen too, and I'm capable of just staring into space and daydreaming.
2. I fall asleep during the day. I've tried getting more hours of sleep at night and it doesn't solve the problem. When I'm bored or confused, my body says "Naptime!" It can be quite embarrassing.
3. I often feel too tired/demotivated/bummed to do errands. A lot of stuff, some more important and some less important, slips through my fingers. The most important, to my quality of life, are buying necessities and cleaning my room -- I tend to put these off much too long for my own good.
4. I don't have enough measures of how well I'm doing as a student. I get confused by some abstract concepts, and sometimes I don't even notice that I'm confused.
5. I like being happy and entertained better than being stressed and bored and confused. This makes me want to work less. Not proud of this character trait but not sure how I can rewire my preferences.
Planned Solutions So Far
1. Work in a cubicle, with no computer, with a kitchen timer to keep me mindful of how many hours I spend working.
2. Plan out the material I have to learn and the time I have to learn it, and make a kibotzer.com account to see if I'm on track for my goal.
3. Track various measures of productivity (hours worked, concepts learned, problems solved, percent correct) with a Joe's Goals account. Have thresholds that I don't want to drop below.
4. Use Self Control to block all my entertainment internet sites during "working hours" (I'll leave early mornings and/or late nights free.)
5. Accumulate diverse library books relevant to coursework, and various sources of practice problems, and more notebooks and paper than I need; don't let lack of physical resources limit my progress.
6. Set aside a regular occasion for clean-up and errands.
Any other advice?
In particular, I don't know what to do about my sleepiness problem. I'm not a very regular caffeine drinker; I've started to drink Lipton tea, but I don't think I've reached the quantity sufficient to keep me awake yet, at 2-3 cups a day.
Any advice on the psychological front would also be helpful. How to stay motivated. I know what my motivation is (the consequences of failure in my situation are not pleasant) but how to keep focused on the importance of my goal, without spending all my time being miserable and frightened because I'm visualizing the worst-case scenario. I know I can fuel myself on guilt for a short time, but I don't like it much and I don't think it's practical long-term.
Yes, of course I'm aware that adults know how to work to achieve what they want. Somehow I've reached adulthood without really developing all the personal capacities that I should have. It's lousy of me, but this is where I am, and I'm ready to change and willing to take advice.