Death_Korps_Kommissar said:
Can anyone lend some advice?
Simply do not allow yourself to play those video games. At least not until you've put in a decent study session.
Set up some sort of schedule where you study on a regular basis. Every day, for a couple hours, max. You don't want to study for longer periods of time, otherwise you'll burn out.
If you're having trouble sitting down and actually focusing, use something as a reward for after you've studied, like those video games. As for staying focused during, try some music. It's okay to stop studying every few minutes to bob to that tune. Allowing yourself to stop from time to time, even if only for a few minutes, will help alleviate any stress you're feeling because you're forcing yourself to study. The more of a routine you get into, the better you'll feel about actually studying.
Also, rewriting something you've just read, or your notes can also help. The more you write something, in your own words, the easier it becomes to remember it.
When you've managed to sit down and study for a while, then allow yourself to play a video game, you'll find yourself feeling like you've actually accomplished something, and that you deserve to play that video game. The more often you study, the better it'll feel. May even make it easier for every consecutive session. Best of luck.