ObiHey man, don't get down I've been in that exact same scenario. It's like this weird limbo of playing video games, being mediocre at school, and feeling like a burden to those around you.
What I've found that helps is regimenting your day, your week, and your month. Figure out all the important stuff you need to do for school, put it on a calendar. Have an agenda for the week (repeat the same things you need for the month). Have a daily schedule that you try and adhere to.
Most of this stuff will have overlap, but it'll drill a certain consistency into you (idk about the dm thing though mines still shit).
I've done this every time I've felt overwhelmed by the amount of assignments and work I've had to do. I can break down an assignment I have to do into a bunch of chunks and work on everything little by little.
Best part about this is that it takes the idea of "Oh fuck I have 5 huge assignments due in two weeks," down to, "Oh all I have to do is write an introduction today? Cool." It gives me a bunch of subgoals to hit day to day that seems a lot more manageable, and also helps me track progress.