I think you've reached an important point where you are able to see it as an enemy to your happiness in life, and that you have a serious self control problem. That is a significant first step. For me, my game addiction was causing all kind of wrist problems, in addition to making me feel crappy about my lack of life/productivity.
A couple insights:
1. What did it for me, after reaching that "moment of clarity", was quitting cold turkey. The trick was.. and you will not like this.. to throw them out. Uninstall them and delete them including your profile and trash the installers. You might reinstall a demo version or something and have some relapses, but after the relapse has run its course, delete it again.
2. Look at it exactly like an addiction. Use similar strategies that alcoholics use to fight their addictions. I'm completely serious. For one, never play games again. Some people can handle these things in moderation. You're not one of them. Look at games exactly like an alcoholic looks at drinks. They are your enemy and they want to kill your happiness.
3. It doesn't end with games. I have since substituted other things.. fortunately not as bad in terms of time consumption though, and fortunately not substances. Hacker News, for example.
The root problem for me isn't specifically about games. It's that when I feel "nervous" about doing work that's tough or unpleasant, my body knows that games / writing on HN / insert other pleasant distraction will take that nervous feeling away. For the moment. That's very much like an addict's mentality. It takes a lot of breathing exercises and focus on my future happiness to overcome those moments.
"Time management" techniques usually don't help because it's a different part of you than your rational mind. It's your body reacting physically to the queasy feeling in your stomach you get of sitting down to do that task you need to do in front of 82 more tasks before you get that serotonin payoff for a job well done. Your body has learned, "but a game can give me that right now, let's just go do that!" Your mind already knows what's best in the long run. You need to untrain your body.
Maybe it's similar for you, maybe it's different. Battling addictions is a big topic and everyone is different. But there is hope. You're lucky that the games you're addicted to can be uninstalled and thrown out. It doesn't stop you from relapsing but it does create a barrier that helps.